The SPI (Serial Peripheral Interface) is a synchronous serial communication protocol used for communication between devices. It uses a master-slave architecture with a single master device initiating data transfer. Key features include using separate clock and data lines, operating in full duplex mode, and allowing multiple slave devices through individual chip selects. It provides a lower pin count solution than parallel buses at the cost of slower communication speeds.
Serial Peripheral Interface (SPI) is an interface bus commonly used to send data between microcontrollers and small peripherals such as shift registers, sensors, and SD cards.
SPI is a serial bus standard established by Motorola and supported in silicon products from various manufacturers.
It is a synchronous serial data link that operates in full duplex (signals carrying data go in both directions simultaneously).
Devices communicate using a master/slave relationship, in which the master initiates the data frame. When the master generates a clock and selects a slave device, data may be transferred in either or both directions simultaneously.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers. Each I2C slave device needs an address – they must still be obtained from NXP (formerly Philips semiconductors).
This presentation discusses the details of the I2C protocol and interfacing of EEPROM with 8051 based on I2C protocol. It also discusses the other applications of I2C protocol
Serial Peripheral Interface (SPI) is an interface bus commonly used to send data between microcontrollers and small peripherals such as shift registers, sensors, and SD cards.
SPI is a serial bus standard established by Motorola and supported in silicon products from various manufacturers.
It is a synchronous serial data link that operates in full duplex (signals carrying data go in both directions simultaneously).
Devices communicate using a master/slave relationship, in which the master initiates the data frame. When the master generates a clock and selects a slave device, data may be transferred in either or both directions simultaneously.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers. Each I2C slave device needs an address – they must still be obtained from NXP (formerly Philips semiconductors).
This presentation discusses the details of the I2C protocol and interfacing of EEPROM with 8051 based on I2C protocol. It also discusses the other applications of I2C protocol
Serial peripheral Interface - Embedded System ProtocolAditya Porwal
Serial Peripheral Interface (SPI) is a synchronous serial data protocol used by micro-controllers for communicating with one or more peripheral devices quickly over short distances. It can also be used for communication between two micro-controllers.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems.
Communication protocols in Embedded Systems. This presentation focused mainly on lower level protocols. Ideal for the beginner to build understanding on these protocols like I2C, USB, SPI etc.
Communication protocols (like UART, SPI, I2C) play an very important role in Micro-controlled based embedded systems development. These protocols helps the main board to communicate with different peripherals by interfacing mechanism. Here is a presentation that talks about how these protocols actually work.
This Presentation describes the ARM CORTEX M3 core processor with the details of the core peripherals. Soon a CORTEX base controller(STM32F100RBT6) ppt will be uploaded. For more information mail me at:gaurav.iitkg@gmail.com.
Serial peripheral Interface - Embedded System ProtocolAditya Porwal
Serial Peripheral Interface (SPI) is a synchronous serial data protocol used by micro-controllers for communicating with one or more peripheral devices quickly over short distances. It can also be used for communication between two micro-controllers.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems.
Communication protocols in Embedded Systems. This presentation focused mainly on lower level protocols. Ideal for the beginner to build understanding on these protocols like I2C, USB, SPI etc.
Communication protocols (like UART, SPI, I2C) play an very important role in Micro-controlled based embedded systems development. These protocols helps the main board to communicate with different peripherals by interfacing mechanism. Here is a presentation that talks about how these protocols actually work.
This Presentation describes the ARM CORTEX M3 core processor with the details of the core peripherals. Soon a CORTEX base controller(STM32F100RBT6) ppt will be uploaded. For more information mail me at:gaurav.iitkg@gmail.com.
Protocol layers are a hierarchical model of network or communication functions. The divisions of the hierarchy are referred to as layers or levels, with each layer performing a specific task. In addition, each protocol layer obtains services from the protocol layer below it and performs services for the protocol layer above it. The Bluetooth system divides communication functions into protocol layers.
The Bluetooth system consists of many existing protocols that are directly used or have been adapted to the specific use of the Bluetooth system. Protocols are often divided into groups that are used for different levels of communication (a protocol stack). Lower level protocols (such as protocols that are used to manage a radio link between specific points) are only used to create, manage, and disconnect transmission between specific points. Mid-level protocols (such as transmission control protocols) are used to create, manage, and disconnect a logical connection between endpoints that may have multiple link connections between them. High level protocols (application layer protocols) are used to launch, control, and close end-user applications.
Some of the layers associated with the Bluetooth system include the baseband layer (physical layer), link layer, host controller interface (HCI), logical link control applications protocol (L2CAP), RF Communications protocol (RFCOMM), Object Exchange (OBEX), and service discovery.
This ppt explains in brief what actually is arm processor and it covers the first 3 chapters of book "ARM SYSTEM DEVELOPERS GUIDE". The 3 chapters include the history,architecture,instruction set etc.
Lot of book tells about what is programming. Many also tell how to write a program, but very few cover the critical aspect of translating logic into a program. Specifically, in this fast paced industry, when you don't have time to think to program, this course comes really handy. It builds on the basics of programming, smooth sailing through the advanced nitty-gritty’s of the Advanced C language by translating logic to code
Object-Oriented Design: Multiple inheritance (C++ and C#)Adair Dingle
Software Design provides options for structural relationships, such as composition vs. inheritance. Each such option defines malleable and stable characteristics of class dependencies and interface provisions. Software designers must evaluate the short- and long-term costs and benefits of design decisions, such as the simulation of inheritance with composition.
Coming up with optimized C program for Embedded Systems consist of multiple challenges. This presentation talks about various methods about optimizing C programs in Embedded environment. It also has some interesting tips, Do's and Dont's that will offer practical help for an Embedded programmer.
* What are Embedded Systems?
* C for Embedded Systems vs. Embedded C.
* Code Compilation process.
* Error types.
* Code Compilation using command line.
its only for learning purpose for beginners who wants to understand this protocol.
Life is all about learning, hope u will enjoy in this my PPT.
for any suggestion your always welcome .
I²C (Inter-Integrated Circuit), pronounced I-squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (now NXP Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers. Alternatively I²C is spelled I2C (pronounced I-two-C) or IIC (pronounced I-I-C).
Since October 10, 2006, no licensing fees are required to implement the I²C protocol. However, fees are still required to obtain I²C slave addresses allocated by NXP.[1]
Several competitors, such as Siemens AG (later Infineon Technologies AG, now Intel mobile communications), NEC, Texas Instruments, STMicroelectronics (formerly SGS-Thomson), Motorola (later Freescale), and Intersil, have introduced compatible I²C products to the market since the mid-1990s.
SMBus, defined by Intel in 1995, is a subset of I²C that defines the protocols more strictly. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern I²C systems incorporate policies and rules from SMBus, sometimes supporting both I²C and SMBus, requiring only minimal reconfiguration.
The Serial Peripheral Interface (SPI) bus is a synchronous serial communication interface specification used for short distance communication, primarily in embedded systems. The interface was developed by Motorola and has become a de facto standard. Typical applications include sensors, Secure Digital cards, and liquid crystal displays.
SPI devices communicate in full duplex mode using a master-slave architecture with a single master. The master device originates the frame for reading and writing. Multiple slave devices are supported through selection with individual slave select (SS) lines.
Sometimes SPI is called a four-wire serial bus, contrasting with three-, two-, and one-wire serial buses. The SPI may be accurately described as a synchronous serial interface,[1] but it is different from the Synchronous Serial Interface (SSI) protocol, which is also a four-wire synchronous serial communication protocol, but employs differential signaling and provides only a single simplex communication channel.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
2. Need of Serial Bus Protocol
• Peripheral devices in embedded systems =>
parallel address and data bus => lots of wiring and
requires number of pins => additional decoding logic
required.
• To reduce the pins and wiring => cost => Serial bus
protocol => SPI (4-wire) & I2C (2-wire).
• Penalty => Slower communication.
3. Various Serial Bus Protocol
• UART
• SPI –Embedded System Protocol
• I2C- Embedded System Protocol
• CAN
• USB
• SATA etc..
4. • The Serial Peripheral Interface Bus or SPI bus is a
synchronous serial data link standard named by
Motorola that operates in full duplex mode.
• Devices communicate in master/slave mode where
the master device initiates the data frame. Multiple
slave devices are allowed with individual
slave select (chip select) lines.
5. •During a data transfer the master always sends 8
to 16 bits of data to the slave, and the slave always
sends a byte of data to the master.
• Maximum data bit rate is one eighth of the input
clock rate.
6. • One Central device (Master), initiates communication
with all slaves.
• No address decoding logic required.
• SPI Master wishes to send the data to slave or request
information from the slave, it activates the clock
signal.
• Master generates information on one line (MOSI)
while samples (read) from another line (MISO).
7. SPI Pin Description
• SCLK — Serial Clock (output from master)
• MOSI — Master Output, Slave Input (output from
master)
• MISO — Master Input, Slave Output (output from
slave)
• SS — Slave Select (active low; output from master)
9. Pin Name :SCK (Serial Clock)
Type :Input / Output
• The SPI used clock signal to synchronize the
transfer of data across the SPI interface.
• The SCK is always driven by the master and
received by the slave, The clock is programmable to
be active high or active low.
•The SCK is only active during a data transfer. Any
other time, it is either in its inactive state, or tri-
stated.
10. Pin Name : MISO
(Master in Slave out)
Type : Input / Output
• The MISO signal is a unidirectional signal used to
transfer serial data from the slave to the master.
• When a device is a slave, serial data is output on
this signal.
• When a device is a master, serial data is input on
this signal.
• When a slave device is not selected, the slave
drives the signal high impedance.
11. Pin Name : MOSI
(Master out Slave in)
Type : Input / Output
• The MOSI signal is a unidirectional signal used to
transfer serial data from the Master to the Slave.
•When a device is a Master, serial data is output on
this signal.
• When a device is a Slave, serial data is input on this
signal.
12. Pin Name : SSEL (Slave Select)
Type : Input
• The SPI slave select signal is an active low signal
that indicates which slave is currently selected to
participate in a data transfer.
• Each slave has its own unique slave select signal
input.
•The SSEL must be low before data transactions
begin and normally stays low for the duration of the
transaction.
• If the SSEL signal goes high any time during a data
transfer, the transfer is considered to be aborted.
13. • In this event, the slave returns to idle, and any data that was
received is thrown away. There are no other indications of
this exception.
•This signal is not directly driven by the master. It could be
driven by a simple general purpose I/O under software
control.
•On the LPC2300 the SSEL pin can be used for a different
function when the SPI interface is only used in Master mode.
• For example, pin hosting the SSEL function can be
configured as an output digital GPIO pin and it is also used
to select one of the SPI slaves.
14. Operation
• The SPI bus can operate with a single master
device and with one or more slave devices.
• SPI bus: single master and single slave
15. • If a single slave device is used, the SSEL pin may
be fixed to logic low if the slave permits it.
• Some slaves require the falling edge (high->low
transition) of the slave select to initiate an action
such as the MAX1242 by Maxim, an ADC, that
starts conversion on said transition.
16. Configuration
• Two types multiple slave configuration:
• Typical SPI bus: Master and independent Slaves
• Daisy-Chained SPI bus: Master and cooperative slaves
17. Typical SPI Bus
• With multiple slave devices, an independent
SSEL signal is required from the master for
each slave device (3).
18. • In the independent slave configuration, there is an
independent slave select line for each slave. This is the way
SPI is normally used.
• Since the MISO pins of the slaves are connected together,
they are required to be tri-state pins.
20. • Some products with SPI bus are designed to be capable of
being connected in a daisy chain configuration, the first
slave output being connected to the second slave input, etc.
• The SPI port of each slave is designed to send out during
the second group of clock pulses an exact copy of what it
received during the first group of clock pulses.
•Such a feature only requires a single SSEL line from the
master, rather than a separate SSEL line for each slave.
21. Points
• Not have ack mechanism to confirm receipt of data
and does not have flow control.
• SPI Master, not have knowledge of whether slave
exist or Not
• Not particular addressing scheme.
• Not defined any maximum data rate.
22. Data Transmission
• A typical hardware setup using two shift registers to
form an inter-chip circular buffer
23. • To begin a communication, the master first
configures the Clock, using a frequency less than
or equal to the maximum frequency the slave
device supports.
•Such frequencies are commonly in the range of
1-70 MHz.
•The master then pulls the slave select SSEL low
for the desired chip.
•During each SPI clock cycle, a full duplex data
transmission occurs.
24. •The master sends a bit on the MOSI line; the slave
reads it from that same line
• The slave sends a bit on the MISO line;
the master reads it from that same line
•Transmissions normally involve two shift registers
of some given word size, such as eight bits, one in
the master and one in the slave; they are connected
in a ring.
25. •After that register has been shifted out, the master
and slave have exchanged values.
•Then each device takes that value and does
something with it, such as writing it to memory.
• If there are more data to exchange, the shift
registers are loaded with new data and the process
repeats.
26. Clock Polarity and Phase
• In addition to setting the clock frequency, the
master must also configure the clock polarity and
phase with respect to the data.
• SPI Block Guide names these two options as CPOL
and CPHA respectively, and most vendors have
adopted that convention.
28. At CPOL=0, the base value of the clock is zero
• For CPHA=0, data are read on the clock's
rising edge (low->high transition) and data are
changed on a falling edge (high->low clock
transition).
• For CPHA=1, data are read on the clock's
falling edge and data are changed on a rising
edge.
29. At CPOL=1, the base value of the clock is one
(inversion of CPOL=0)
• For CPHA=0, data are read on clock's falling
edge and data are changed on a rising edge.
• For CPHA=1, data are read on clock's rising
edge and data are changed on a falling edge.
30. CPOL &
CPHA
First data driven Other data
driven
Data
Sampled
0 & 0 Prior to first
SCK rising edge
SCK falling
edge
SCK rising
edge
0 & 1 First SCK rising
edge
SCK rising
edge
SCK falling
edge
1 & 0 Prior to first
SCK falling
edge
SCK rising
edge
SCK falling
edge
1 & 1 First SCK
falling edge
SCK falling
edge
SCK rising
edge
32. • 8-bit data transfer, device is master/slave and setting
of CPHA variable.
•Device, Master => Start of transfer, master having a
data ready to transfer. Activate the clock and begin the
transfer.
•Device, Slave and CPHA=0, transfer start when
SSEL=0.
•Device, Slave and CPHA=1, transfer starts on first
clock edge when slave is selected.
33. Mode Numbers
• The combinations of polarity and phases are
often referred to as modes
Mode CPOL CPHA
0 0 0
1 0 1
2 1 0
3 1 1
34. Register Description
• SPI has seven registers, from that programmers
interface for SPI peripheral has five registers.
• The bits in the rest of two TEST registers are
intended for functional verification only.
35. Name Description Access
S0SPCR SPI Control Register.
This register controls the R/W
operation of the SPI.
S0SPSR SPI Status Register.
This register shows the R0
status of the SPI.
36. Name Description Access
S0SPDR SPI Data Register.
This bi-directional
register provides the R/W
transmit and receive
data for the SPI.
37. Name Description Access
S0SPCCR SPI Clock Counter Register.
This register controls the R/W
frequency of a master’s SCK
S0SPINT SPI Interrupt Flag.
This register contains the R/W
interrupt flag for the
SPI interface.
38. (1) SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
1:0 - Reserved, user software
should not write ones to
reserved bits.
39. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
2 BitEnable 0 The SPI controller sends
and receives 8 bits of data
per transfer.
1 The SPI controller sends and
receives the number of bits
selected by bits 11:8.
40. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
3 CPHA Clock phase control
0 Data is sampled on the first
clock edge of SCK.
1 Data is sampled on the
second clock edge of the
SCK.
41. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
4 CPOL Clock polarity control.
0 SCK is active high.
1 SCK is active low.
5 MSTR Master mode select.
0 The SPI operates in Slave
mode.
1 The SPI operates in Master
mode.
42. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
6 LSBF LSB First, controls in which
direction each byte is
shifted when transferred.
0 SPI data is transferred MSB
(bit 7) first.
1 SPI data is transferred LSB
(bit 0) first.
43. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
7 SPIE Serial peripheral interrupt
enable.
0 SPI interrupts are inhibited.
1 A hardware interrupt is
generated each time the
SPIF or MODF bits are
activated.
44. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
11:8 BITS When bit 2 of this register is
1, this field controls the
number of bits per transfer:
1000 8 bits per transfer
1001 9 bits per transfer
1010 10 bits per transfer
1011 11 bits per transfer
45. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
1100 12 bits per transfer
1101 13 bits per transfer
1110 14 bits per transfer
1111 15 bits per transfer
0000 16 bits per transfer
46. SPI Control Register
(S0SPCR - 0xE002 0000)
Bit Symbol Value Description
15:12 - Reserved, user software
should not write ones to
reserved bits.
47. (2) SPI Data Register
(S0SPDR - 0xE002 0008)
• This bi-directional data register provides the
transmit and receive data for the SPI.
• Transmit data is provided to the SPI by writing
to this register.
• Data received by the SPI can be read from this
register.
49. • There is no buffer between the data register and
the internal shift register. A write to the data
register goes directly into the internal shift
register.
• Therefore, data should only be written to this
register when a transmit is not currently in
progress.
50. • Read data is buffered.
• When a transfer is complete, the receive data is
transferred to a single byte data buffer, where it
is later read.
• A read of the SPI data register returns the value
of the read data buffer.
51. SPI Data Register
(S0SPDR - 0xE002 0008)
Bit Symbol Description
7:0 DataLow SPI bi-directional data port.
15:8 DataHigh If bit 2 of the SPCR is 1 and bits
11:8 are other than 1000, some
or all of these bits contain the
additional transmit and receive
bits. When less than 16 bits are
selected, the most significant
among these bits read as zeroes.
52. (3) SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
7 SPIF SPI transfer complete flag.
When 1, this bit indicates when a
SPI data transfer is complete.
When a master, this bit is set at the
end of the last cycle of the transfer.
53. SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
7 SPIF SPI transfer complete flag.
When a slave, this bit is set on the
last data sampling edge of the SCK.
This bit is cleared by first reading
this register then accessing the SPI
data register.
54. SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
6 WCOL Write Collision. When 1, this bit
indicates that a write collision has
occurred. This bit is cleared by
reading this register then accessing
the SPI data register.
55. Exception conditions –Write Collision
• As stated previously, there is no write
buffer between the SPI block bus
interface, and the internal shift register.
• As a result, data must not be written to
the SPI data register when a SPI data
transfer is currently in progress.
56. • The time frame where data cannot be written to the
SPI data register is from when the transfer starts,
until after the status register has been read when the
SPIF status is active.
•If the SPI data register is written in this time frame,
the write data will be lost, and the write collision
(WCOL) bit in the status register will be activated.
57. SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
5 ROVR Read overrun. When 1, this bit
indicates that a read overrun has
occurred. This bit is cleared by
reading this register.
58. Exception conditions –Read Overrun
• A read overrun occurs when the SPI block internal
read buffer contains data that has not been read by the
processor, and a new transfer is completed.
• The read buffer containing valid data is indicated by
the SPIF bit in the status register being active.
59. Exception conditions –Read Overrun
•When a transfer completes, the SPI block needs to
move the received data to the read buffer.
• If the SPIF bit is active (the read buffer is full),
the new receive data will be lost, and the read
overrun (ROVR) bit in the status register will be
activated.
60. SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
4 MODF Mode fault. when 1, this bit
indicates that a Mode fault error
has occurred. This bit is cleared
by reading this register, then
writing the SPI Control register.
61. Exception conditions –Mode Fault
• If the SSEL signal goes active, when the SPI
block is a master, this indicates another master has
selected the same device to be a slave. This
condition is known as a mode fault.
• When a mode fault is detected, the mode fault
(MODF) bit in the status register will be activated.
62. SPI Status Register
(S0SPSR - 0xE002 0004)
Bit Symbol Description
3 ABRT Slave abort. When 1, this bit
indicates that a slave abort has
occurred. This bit is cleared by
reading this register.
2:0 - Reserved, user software should not
write ones to reserved bits.
63. Exception conditions –Slave Abort
• A slave transfer is considered to be aborted,
if the SSEL signal goes inactive before the
transfer is complete.
• In the event of a slave abort, the transmit and
receive data for the transfer that was in
progress are lost, and the slave abort(ABRT)
bit in the status register will be activated.
64. SPI Interrupt Register
(S0SPINT - 0xE002 001C)
• This register contains the interrupt flag for the
SPI interface.
Bit Symbol Description
0 SPI SPI interrupt flag. Set by the SPI
Interrupt interface to generate an interrupt.
Flag Cleared by writing a 1 to this bit.
7:1 - Reserved, user software should
not write ones to reserved bits.
65. SPI Clock Counter Register
(S0SPCCR - 0xE002 000C)
• This register controls the frequency of a
master’s SCK.
• The register indicates the number of PCLK
cycles that make up an SPI clock.
• The value of this register must always be
an even number. As a result, bit 0 must always
be 0.
67. Configuration - Master operation
• The following sequence describes how
one should process a data transfer with
the SPI block when it is set up to be the
master.
• This process assumes that any prior
data transfer has already completed.
68. Configuration - Master operation
1. Set the SPI Clock counter register to
the desired clock rate.
2. Set the SPI Control register to the
desired settings.
3. Write the data that transmitted to the
SPI data register. This write starts the
SPI data transfer.
69. Configuration - Master operation
4. Wait for the SPIF bit in the SPI status
register to be set to 1. The SPIF bit
will be set after the last cycle of the
SPI data transfer.
5. Read the SPI status register.
70. Configuration - Master operation
6. Read the received data from the SPI
data register (optional).
7.Go to step 3 if more data is required
to transmit.
71. Configuration - Master operation
NOTE:
• A read or write of the SPI data register
is required in order to clear the SPIF
status bit.
• Therefore, if the optional read of the
SPI data register does not take place, a
write to this register is required in
order to clear the SPIF status bit.
72. Configuration - Slave operation
• The following sequence describes how
one should process a data transfer with
the SPI block when it is set up to be the
slave.
• This process assumes that any prior
data transfer has already completed.
73. Configuration - Slave operation
1. Set the SPI control register to the
desired settings.
2. Write the data to transmitted to the SPI
data register (optional). Note that this
can only be done when a slave SPI
transfer is not in progress.
74. Configuration - Slave operation
3. Wait for the SPIF bit in the SPI status
register to be set to 1. The SPIF bit
will be set after the last sampling
clock edge of the SPI data transfer.
4. Read the SPI status register.
75. Configuration - Slave operation
5. Read the received data from the SPI
data register (optional).
6. Go to step 2 if more data is required to
transmit.
76. Configuration - Slave operation
NOTE:
• A read or write of the SPI data register
is required in order to clear the SPIF
status bit.
• Therefore, at least one of the optional
reads or writes of the SPI data register
must take place, in order to clear the
SPIF status bit.
77. SPI- Master (C-Code)
• #Include <LPC2300.h>
• Void init (void)
• # define SPIF (1<<7)
• # define data 0xC1
• int main ()
• {
• Init(); // function call
• While (1)
• {
• SPDR= data; // write data out
• While (!(SPSR& SPIF)) { }
• }
• }
• Void init () // fun declared
• {
• PINSEL0=0xAA000;
(SCK1, SSEL1, MOSI1,MISO1)
• VBPDIV=0x1;// set PCLK to
same as CCLk
• SPCR= 0x20;// device selected
master
• }
81. Advantages
• Full duplex communication
• Higher throughput than I²C
• Complete protocol flexibility for the bits
transferred
* Not limited to 8-bit words
* Arbitrary choice of message size,
content, and purpose
82. Advantages
• Extremely simple hardware interfacing
* Typically lower power requirements than
I²C due to less circuitry
* No arbitration or associated failure modes
* Slaves use the master's clock, and don't
need precision oscillators
* Transceivers are not needed
83. Disadvantages
• Requires more pins on IC packages than
I²C, even in the "3-Wire" variant
• No hardware flow control
• No hardware slave acknowledgment (the
master could be "talking" to nothing and not
know it)
84. Disadvantages
• Supports only one master device
• Only handles short distances compared
to RS-232, RS-485, or CAN-bus
85. Applications
SPI is used to talk to a variety of
peripherals, such as:
•Sensors: Temperature, pressure, ADC,
touch-screens
•Control devices: audio codecs, digital
potentiometers, DAC
86. Applications
• Memory: flash and EEPROM
• Real-time clocks
• LCD displays, sometimes even for
managing image data
• Any MMC or SD card