TQ210 bare metal programming (3) - keystroke (query method)

First, check the bottom board schematic diagram of TQ210

This time, only KEY1 and KEY2 are operated. Search for XEINT0 in the TQ210 core board schematic diagram.

It can be seen that KEY1 and KEY2 are connected to the GPH0_0 and GPH0_1 pins of S5PV210 respectively.

This programming uses the query method. You need to set these two pins to input mode, and then read the pin status in a loop. When the user presses the button, the corresponding pin is at a low level and the LED status changes.

View S5PV210 chip manual

start.S

.global _start @Declare a global label

_start:

bl main @jump to C function to execute

halt:

b halt @Dead loop

key.c

#define GPC0CON *((volatile unsigned int *)0xE0200060)

#define GPC0DAT *((volatile unsigned int *)0xE0200064)

#define GPH0CON *((volatile unsigned int *)0xE0200C00)

#define GPH0DAT *((volatile unsigned int *)0xE0200C04)

void delay(volatile unsigned int t)

{

volatile unsigned int t2 = 0xFFFF;

while (t--)

for (; t2; t2--);

}

int main()

{

int key_val = 0;

int bit;

GPC0CON &= ~(0xFF << 12);

GPC0CON |= 0x11 << 12; // Configure GPC0_3 and GPC0_4 as outputs: LED1 and LED2

GPH0CON &= ~(0xFF << 0); // Configure GPH0_0 and GPH0_1 as input: key1 and key2

while (1)

{

key_val = GPH0DAT & 0x3;

if (key_val)

{

delay(500000); // Anti-shake delay

key_val = GPH0DAT & 0x3;

if (key_val)

{

if (0x01 == key_val) // key1

GPC0DAT ^= 1 << 3; // toggle LED1

else if (0x02 == key_val) // key2

GPC0DAT ^= 1 << 4; // toggle LED2

}

}

}

return 0;

}

Makefile

key.bin: start.o key.o

arm-linux-ld -Ttext 0x20000000 -o key.elf $^

arm-linux-objcopy -O binary key.elf $@

arm-linux-objdump -D key.elf > key.dis

key.o : key.c

arm-linux-gcc -c $< -o $@

start.o : start.S

arm-linux-gcc -c $< -o $@

clean:

rm *.o *.elf *.bin *.dis

For the download method, please refer to "TQ210 Bare Metal Programming (1) - Lighting up an LED"

After downloading the program:

Press key1, LED1 lights up, press key1 again, LED1 turns off

Press key2, LED2 lights up, press key2 again, LED2 turns off