D–6
Writing a Parallel Communication Driver
Publication 17706.5.20 - June 1997
If there is no more to send, the KFC15/KFCD15:
1. Sets pin 15 (Error) and pin 12 (P. End) to 1.
2. Sets pin 10 (Acknowledge) to 1.
and the host sets pin 17 (Select Input) to 1.
Data Transfer in Nibble Mode
To send data in Nibble mode from the KFC15/KFCD15 to the host,
the KFC15/KFCD15:
1. Checks that the host’s pin 14 (Auto Feed) is set to 0.
2. Places the lower nibble on the handshaking lines.
3. Sets pin 10 (Acknowledge) to 0 then 1.
To receive the lower nibble, the host:
1. Sets pin 14 (Auto Feed) to 1.
2. Reads the data.
3. Sets pin 1 (Strobe) to 0 then 1.
4. Sets pin 14 (Auto Feed) to 0.
To send the upper nibble, the KFC15/KFCD15:
1. Checks that the host’s pin 14 (Auto Feed) is set to 0.
2. Places the upper nibble on the handshaking lines.
3. Sets pin 10 (Acknowledge) to 0 then 1.