This document provides an introduction to pins, ports, and configuring pins on the ARM LPC2148 microcontroller. It discusses pin configuration, the different ports on the LPC2148, and how to configure pins as inputs, outputs, or alternate functions using the various IO registers. It also provides an example program for blinking an LED connected to pin P1.16 to demonstrate basic pin configuration and output. The document concludes with an assignment to draw the LED blinking circuit and modify the program to blink LEDs on pins P0.16 through P0.23.

1. ARM LPC2148 Training
Class - 1
Topic : Introduction to Pin’s,
PORTS and Configuring ARM
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2. Topics
• PIN configuration
• PORTS
• Configuring PIN’s
• Simple LED blinking program
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3. PIN Configuration
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Fig : 1 PIN Diagram of LPC2148

4. PIN Configuration (Cont..)
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LPC2148
PORT 0 PORT 1
P0.0 to P0.15 , P0.16 to P0.31 P1.0 to P1.15 , P1.16 to P1.31
Fig : 2 Distribution of PORT’s and PIN’s

5. PORTx
PORT 0:
• P0.0 to P0.15 → Lower 16 bit Pins
• P0.17 to P0.31 → Higher 16 bit Pins
PORT 1:
• P1.0 to P1.15 → Lower 16 bit Pins
• P1.17 to P1.31 → Higher 16 bit Pins
PORT 0 – Lower 16 bit and higher 16 bit
are used as GPIO pins
PORT 1 – Only higher 16 bit pins are used
as GPIO pins.
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6. PORTx (Cont..)
• Pins of P1.0 to P1.15 of lower 16 bit pins
are not available for the user.
• Also P0.24, P0.26 and P0.27 are not
available for user.
• Out of 64 pins only user can use 45 Pins
of LPC2148.
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7. Configuring PIN’s
• To use the 45 pins we must configure the pins by
configuring the following registers.
• IOxPIN/IOPINx → IO pin Status register
• IODIRx → Direction register
• IOSETx → State set register
• IOCLRx → PIN Clear register
• All the registers are 32 bit registers each bit
controls the each pin of LPC2148.
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8. Configuring PIN’s
IOPINx – IO Pin Status register
Px.31 Px.27 Px.23 Px.19 Px.15 Px.11 Px.7 Px.3 Px.0
0000 0000 0000 0000 0000 0000 0000 0000
This can be written in the Hexa Decimal format
0 x 0 0 0 0 0 0 0 0
0x stands for hexa decimal deceleration
• Reading the values of pins can be done by
IOPINx
Ex: IOPIN0 = 0x0000000F
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9. Configuring PIN’s (Cont…)
IODIRx - Direction register
• Assigning 0 → will make pin as INPUT
• Assigning 1 → will make pin as OUTPUT
• By default the pin value will be set as ‘0’
• If we want to change the pin P0.0 to P0.3
as OUTPUT pins then declaration will be
Ex: 0 x 0 0 0 0 0 0 0 F
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10. Configuring PIN’s (Cont…)
IOSETx - State set register
Ex : 0 x 0 0 0 0 0 0 0 F // Px.0 to Px.3 as High
IOCLRx - PIN Clear register
Ex : 0 x 0 0 0 0 0 0 0 F // Px.0 to Px.3 satus will be
cleared
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11. Configuring PIN’s (Cont…)
S1 S0 O/P
0 0 GPIO
0 1 1st
1 0 2nd
1 1 3rd
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PSB
GPIO
Ist Alternate Function
2nd Alternate Function
Reserve
Px.y
S1 S0
x – 0 or 1
y – 0 to 31
Fig : 3 General Block Diagram of single
Table : 1 Selector Input and PIN State
S1 and S0 values are configured by associated register of PSB

12. Configuring PIN’s (Cont…)
• PSB – Pin Select Block has the following
registers
• PINSEL0 –Controls the pins from P0.0 to P0.15
• PINSEL1 –Controls the pins from P0.16 to P0.31
• PINSEL2 –Controls the pins from P1.16 to P1.31
• Each of the registers are 32 bit wide then how it
controls the 16 bit pins
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13. Configuring PIN’s (Cont…)
• Lets take the example of PINSEL0 32 bit register
which controls the pins from P0.0 to P0.15.
• Similarly the registers of PINSEL1 and PINSEL2
will be distributed to the remaining pins of
corresponding PORTs
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00
P0.12
00
P0.11
00
P0.10
00
P0.9
00
P0.8
00
P0.7
00
P0.6
00
P0.5
00
P0.4
00
P0.3
00
P0.2
00
P0.1
00
P0.0
S1 – S0S1 – S0
Fig : 4 Distribution of 32 bit registers to PINs of PORT 0

14. Configuring PIN’s (Cont…)
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Fig : 5 Datasheet shows the features of PORTO Pins

15. Configuring PIN’s (Cont…)
• Example for configuring P0.0 pin as a Tx Pin for
USART communication
• PINSEL0 = 0 x 0 0 0 0 0 0 0 1
P0.0 become as TxD0 by setting LSB values of P0.3
to P0.0 as 0001
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PSB
GPIO
TxDo
PWM
Reserve
P0.0
S1 S0
Fig : 5 Features of P0.0 pin

16. Simple LED Blinking Program
• Blink the LED connected in PORT1
# include <lpc21xx.h> // Include header file
void delay(void);
int main(void)
{
PINSEL2 = 0x00000000; // Configure P1.16 as GPIO pin
IODIR1 = 0x00000000; // Configure P1.16 as OUTPT pin
while(1) {
IOSET1 = 0x00010000; // Turn ON LED at P1.16
delay(); // Wait for a while
IOCLR1 = 0x00010000; // Turn OFF LED at P1.16
delay(); // Wait for a while
}
}
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17. Simple LED Blinking Program
void delay(void){
unsigned int j; // assign the variable j
for(j=0;j<1000000;j++) // Increment j till
} 1000000
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18. Assignment
• Draw the circuit for the above program
• Write the program for blinking the LED from
P0.16 to P0.23.
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19. Thank You
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