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pc98_usb: Add RDY pulse in response receive #666

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RDY high pulse(>=37us) is required to allow keyboard to send next data.
https://archive.org/stream/PC9800TechnicalDataBookHARDWARE1993/PC-9800TechnicalDataBook_HARDWARE1993#page/n157
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tmk 2021-01-16 23:31:22 +09:00
parent aa8d9fe5e6
commit d73bedb51a
1 changed files with 13 additions and 5 deletions
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18
converter/pc98_usb/matrix.c
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@ -63,6 +63,13 @@ static int16_t pc98_wait_response(void)
int16_t code = -1;
uint8_t timeout = 255;
while (timeout-- && (code = serial_recv2()) == -1) _delay_ms(1);
// Keyboards require RDY pulse >=37us to send next data
// https://archive.org/stream/PC9800TechnicalDataBookHARDWARE1993/PC-9800TechnicalDataBook_HARDWARE1993#page/n157
PC98_RDY_PORT |= (1<<PC98_RDY_BIT);
_delay_us(40);
PC98_RDY_PORT &= ~(1<<PC98_RDY_BIT);
xprintf("r%04X ", code);
return code;
}
@ -176,11 +183,12 @@ uint8_t matrix_scan(void)
}
}
// PC-9801V keyboard requires RDY pulse.
// This is not optimal place though, it works.
PC98_RDY_PORT |= (1<<PC98_RDY_BIT); // RDY: high
_delay_us(20);
PC98_RDY_PORT &= ~(1<<PC98_RDY_BIT); // RDY: low
// Keyboards require RDY pulse >=37us to send next data
// https://archive.org/stream/PC9800TechnicalDataBookHARDWARE1993/PC-9800TechnicalDataBook_HARDWARE1993#page/n157
PC98_RDY_PORT |= (1<<PC98_RDY_BIT);
_delay_us(40);
PC98_RDY_PORT &= ~(1<<PC98_RDY_BIT);
return code;
}