The document discusses various computer peripherals and their interfacing with the CPU. It covers LED and character displays, graphics monitors, keyboards and their hardware and software interfaces. It describes the transmission controller for peripheral control and different modes of data transfer. It also discusses 7-segment decoders, dot matrix displays, and character monitors. Graphics representation and vector vs raster graphics are briefly covered.

1. Dr A Sahu
Dept of Computer Science &
Engineering
IIT Guwahati

2. • Peripheral communications
• Display
• LED Display
– Decoder
– Generic model
– Interfacing
• Character Display Monitor
– Decoder
– Generic Model
• Graphics monitor
– Why graphics? Vector Vs Raster
• Keyboard type and Interfaces

3. • Peripherals : HD monitor, 5.1 speaker
• Interfaces : Intermediate Hardware
– Nvidia GPU card, Creative Sound Blaster card
• Interfaces : Intermediate Software/Program
– Nvidia GPU driver , Sound Blaster Driver software
Processor
R
A
M

4. • Transmission Controller:
– MPU control, Device Control (DMA)
• Type of IO mapping
– Peripheral (IN/Out), Memory mapped IO (LD/ST,MV)
• Format of communication
– Synchronous (T & R sync with clock), Asynchronous
• Mode of Data Transfer
– Parallel, Serial (UART)
• Condition for data transfer
– Uncond., Polling, Interrupt, Ready signal, Handshake

5. 7 Seg 9 Seg 16 Seg 3x5 DotMatix 5x7 9x11
Dot Matrix Display Panel
25x80 character monitor

6. Data
ASCII/BCD
Decoder
Or
Memory
Display
Monitor/LEDs
Time to Decode Time to Display

7. • Data to 7 Segment Decoder
a
b
c
d
e
f
g
Common
Cathode
a
b
c
f
g
e
d
D
C
B
A
LT
RBI
BI
Decoder
5V
1
0
0
0
1
0
1
1
1
0
1
5
5v
5V
1
1
1
1
1
1
1
5
5v
RBO

8. • Data to 7 Segment Decoder
a b c d e f g
D C B A
RBI RBO
a b c d e f g
D C B A
RBI RBO
a b c d e f g
D C B A
RBI RBO
a b c d e f g
D C B A
RBI RBO
a b c d e f g
D C B A
RBI RBO
5V
0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 1 1 1
10
Blank
0
Blank
1 1

9. 40 Bit data line
8 Bit data line
0 1 2 3 4
Data 1
Data 2
Data 3
Data 4
Data 0
Mod 5
Counter

10. 7 Segment Decoder
1:N Decoder
Counter
RAM
590

11. • Write a program to display contents of B,C,D
and E register to LED display
• Write to buffer memory to display to 7 Seg.
LEDs
• Use address FC H,FD H,FE H and FF H to
display

12. LEDs
Buffer
Memory
Address
line
CS WR RD
Data
lines
Ctr
7 Seg.
Decoder
MPU
A7
A6
A5
A4
A3
A2
74LS373
Latches
LE
D7
D6
D5
D4
D3
D2
D1
D0
A1
A0
IO/M
RD
WR

13. • Interface program to Display content of B,C,D
and E after 1 Sec Delay
DIS: MVI A,B
OUT FCH
MVI A,C
OUT FDH
MVI A,D
OUT FEH
MVI A,E
OUT FFH
CALL DELAY ;1sec delay
JMP DIS;

14. 25x80 character monitor
C A T
F I R E
0 1 2 3 4 ….. 78 79
0
1
2
23
24
A
Decoder
Or
ROM
Memory
Decoded
Bits
Row
Ctr
Col
Ctr
CLK > 50Hzx25x80

15. • Delay of Monitor is 1/50 Sec, After Every 50
Second it makes ready
• From stream buffer it writes to Frame buffer after
getting command. (Flush stream command)
Char Frame
Buffer
Memory
Address
line
CS WR
Data
lines
Counter
Stream Buffer
When
C=0Ready
Address (r,c)

16. • LED is very high speed
– You can write to LEDs at very high speed
– Display meant for to see some thing (Is it good?)
• 30 Frames/Sec is more then enough for
human eye (>30 blink make human eye Fixed)
• No of blink > 30Hz
– Human can not differentiate ON/OFF state, it will
be seen AS ON state
• Video display make default 30-60 Frame/Sec
• Monitor run at speed 30-60 Frame/Sec

17. • Speed is fixed (60Frame/Sec)
• $ a.out
• $ a.out > outputfile
• $ a.out > /dev/null
for(i=0;i<10000;i++){
printf(“HelloWorld”);
}

18. • Char display (80x25 char, 5x7pixel=400x175)
• CRT Monitor (400x600, 640x480,600x800)
• LCD Monitor (1024x768,1280x1024,…)
• Graphics visually more appealing
• Display Line, Circle, Rectangle, Curve, Polygon
– Character using this primitives
– True type font
RED ARROW
Circle

19. 1024x768 Pixel LCD
0 1 2 3 4 ….. …1023
0
1
2
767
R
Row
Ctr
Col
Ctr
CLK > 1024x768x50Hz
B G
8x3=24 Bits
Frame Buffer
Refresh screen 50 time a Sec

20. Pixels in Frame
Buffer
1 Bit Per Pixels Pixels on
the Screen
Graphical representation of 1 bit color

21. Pixels in Frame
Buffer
Pixels on
the Screen
15 Bit Per Pixels
Graphical representation of 15 bit color

22. Pixels in Frame
Buffer
Pixels on
the Screen
24 Bit Per Pixels
Graphical representation of 24 bit color

23. 1- bit color 8-bit color 16-bit color

24. • Vector graphics:
– Use geometrical primitives based
on mathematical equations, to
represent images in computer
graphics
– Points, Lines, Curve, shapes or
Polygons
• Raster Graphics: Complementary
to Vector Graphics
– Representation of images as an
array of pixels
– photographic images

25. • Store the primitives in the FILE
– Word, Photoshop, Xfig, GNUPlot, PS, HTML Tag
• Raster: Store the Pixel values in the FILE
– BMP, PNG, JPG
• At runtime, process the primitive and
generate Pixel to raster the screen (Display)
• Who do this?
– Software
– GPU (hardware accelerated routine)

26. • Computer font formats: TrueType Font
– Where each letter is created from Bézier curves
• Many varieties of font for a character
Units
Points with unit
and curve
properties are
stored

27. • GPU : specialized processor that accelerates
3D or 2D graphics primitives operations
• Lots of Floating point operations
• Accelerates Primitives
– Line, circle, polygon, mesh, projection, sphere,

28. 3D application
3D API:
OpenGL
DirectX/3D
3D API Commands
CPU-GPU Boundary
GPU Command
& Data Stream
GPU
Command
Primitive
Assembly
Rastereisation
Interpolation
Raster
Operation
Frame
Buffer
Programmable
Fragment
Processors
Programmable
Vertex
Processor
Vertex Index
Stream
Assembled
polygon, line
& points
Pixel
Location
Stream
Pixel
Updates
Transformed
Fragments
Rastorized
Pretransformed
Fragments
transformed
VerticesPretransformed
Vertices

29. Memory
System
Texture
Memory
Frame
Buffer
Vertex
Processing
Pixel
Processing
Vertices
(x,y,z)
Pixel
R, G,B
Vertex
Shadder
Pixel
Shadder

31. • R S Gaonkar, “Microprocessor Architecture”, Unit II preface,
Chapter 14 and 17