LIV2/AVR-PS2-KBC
1
0
Fork 0
mirror of https://github.com/LIV2/AVR-PS2-KBC.git synced 2025-12-06 00:23:47 +00:00
Code Issues Packages Projects Releases Wiki Activity

Don't drive clk/dat lines

Browse Source 
Only ever pull the lines low and let the pull-ups bring it high to prevent contention
This commit is contained in:
Matt Harlum 2019-11-02 21:19:19 +01:00
parent d249b1161a
commit 3de5204794
1 changed files with 12 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
ps2kbd.c
View File

@ -69,13 +69,12 @@ void sendps2(uint8_t data)
send_byte = data;
send_parity = calc_parity(send_byte);
GIMSK &= ~(1 << INT0); // Disable interrupt for CLK
PORTB |= (1 << PB5); // Data High
DDRB |= (1 << DDB6 | 1 << DDB5); // CLK/Data are now Outputs
PORTB &= ~(1 << PB6); // Bring Clock low
PORTB &= ~(1 << PB5); // Set data Low
PORTB &= ~(1 << PB6); // Set Clock low
DDRB |= (1 << DDB6); // CLK low
_delay_us(150);
PORTB &= ~(1 << PB5); // Bring data Low
PORTB |= (1 << PB6); // Release clock and set it as an input again, clear interrupt flags and re-enable the intterupts
DDRB &= ~(1 << DDB6);
DDRB |= (1 << DDB5); // DATA low
DDRB &= ~(1 << DDB6); // Release clock and set it as an input again, clear interrupt flags and re-enable the interrupts
GIFR |= (1 << INTF0);
GIMSK |= (1 << INT0);
sr = TX;
@ -86,6 +85,7 @@ void sendps2(uint8_t data)
buffer = EMPTY;
send_tries--;
} while ((send_tries) && (scancode != 0xFA)); // If the response is not an ack, resend up to 3 times.
_delay_us(150);
}
int getresponse(void) {
@ -124,27 +124,27 @@ ISR (INT0_vect)
if (send_bitcount >=0 && send_bitcount <=7) // Data Byte
{
if ((send_byte >> send_bitcount) & 1) {
PORTB |= (1 << PB5);
DDRB &= ~(1 << DDB5); // DATA High
}
else
{
PORTB &= ~(1 << PB5);
DDRB |= (1 << DDB5); // DATA Low
}
}
else if (send_bitcount == 8) // Parity Bit
{
if (send_parity)
{
PORTB &= ~(1 << PB5);
DDRB |= (1 << DDB5); // DATA Low
}
else
{
PORTB |= (1 << PB5);
DDRB &= ~(1 << DDB5); // DATA High
}
}
else if (send_bitcount == 9) // Stop Bit
{
PORTB |= (1 << PB5);
DDRB &= ~(1 << DDB5); // DATA High
}
if (send_bitcount < 10)
{
@ -184,7 +184,7 @@ ISR (INT0_vect)
}
rcv_bitcount++;
}
else if (rcv_bitcount >= 10)
else if (rcv_bitcount == 10)
{
ssp |= (result << 1); // Stop Bit
if ((ssp & 0x2) != 0x02) // Check start and stop bits.
@ -388,7 +388,6 @@ int main (void) {
}
}
buffer = EMPTY;
PORTB |= (1 << PB6); // Release clock and set it as an input again, clear interrupt flags and re-enable the interupts
DDRB &= ~(1 << DDB6);
GIFR |= (1 << INTF0);
GIMSK |= (1 << INT0);