Panasonic R435 and others Serial Port

kptypes · 13. Januar 2024

Following up on this thread .. Panasonic R191 I have a similar printer that needs a similar interface. In trying to validate the protocol, I've managed to get this far. But something still isn't right/complete. Could it be a parity bit missing?

Code

void write_byte(char b) {
int bits = 8;
int ackbit = 0;
int timeout = 0;
//state = LOW; // Set flag
while(digitalRead(ACK_IN) == LOW); // Wait until it is high
digitalWrite(CS_OUT, LOW);
delay(1);
while(bits--) {
digitalWrite(DAT_OUT, ( b >> (8-bits) & 0x01 ) ? HIGH : LOW );
delay(10);
while(digitalRead(ACK_IN) == LOW); // Wait until it is high
digitalWrite(CLK_OUT, HIGH);
while(digitalRead(ACK_IN) == HIGH); // Wait until it is LOW
delay(5);
digitalWrite(CLK_OUT, LOW);
while(digitalRead(ACK_IN) == LOW); // Wait until it is high
}
digitalWrite(CS_OUT, HIGH);
delay(10);
}

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kptypes · 15. Januar 2024

Yeah no, this is it. Turns out that with corrupted bytes, it was confusing the results. With a full off/on of the typwriter between tests, that worked better. This is no parity or anything, real simple LSB and 8 bits.

Code

/*
* On Setup :
*  > CLK - set low
* Send byte:
*  > CS - set low
*  -- loop over 8 bits
*    > DAT - set value
*    > CLK - set high
*    < ACK - wait for high pulse
*    > CLK - set low
*  > CS - set high
*/


void write_byte(uint16_t b) {
int bits = 8;
int ackbit = 0;
int timeout = 0;
// Set parity bit
char par = parity(b);


while(digitalRead(ACK_IN) == LOW); // Wait until it is high
digitalWrite(CS_OUT, LOW);
delay(1);
while(bits--) {
digitalWrite(DAT_OUT, ( b >> (7-bits) & 0x01 ) ? HIGH : LOW );
delay(10);
while(digitalRead(ACK_IN) == LOW); // Wait until it is high
digitalWrite(CLK_OUT, HIGH);
while(digitalRead(ACK_IN) == HIGH); // Wait until it is LOW
delay(5);
digitalWrite(CLK_OUT, LOW);
while(digitalRead(ACK_IN) == LOW); // Wait until it is high
}
digitalWrite(CS_OUT, HIGH);
delay(10);
}

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