D–4
Writing a Parallel Communication Driver
Publication 17706.5.20 - June 1997
In Nibble mode, receiving data from the KFC15/KFCD15 module is
a little more complex. The lower nibble of a byte is sent first, then
the upper nibble on the next data block. After the host acknowledges
the upper nibble, the KFC15/KFCD15 acknowledges by setting the
data clock (pin 10) high. At this point, the status indicators Busy (pin
11) and EOT (pins 12 and 15) from the KFC15/KFCD15 can be read
by the host device. The status indicators are overwritten with the
next piece of data when the host Busy pin is reset.
Data Transmission
The following describes the actions that should be taken by both the
host and KFC15/KFCD15 to send and transmit data. Note that 1
means logical 1 or high, regardless of whether or not the signal is
normally active high or active low.
On power up, the host should do the following to initialize
communication:
1. Set pin 1 (Strobe) to 1 and pin 14 (Auto Feed) to 0.
2. Set pin 17 (Select Input) and pin 16 (Initialize Printer) to 0. These
two lines must be be held low for a minimum of 50 ms to allow
the KFC15/KFCD15 to detect them.
To send data from the host computer to the KFC15/KFCD15 the host
should:
1. Set pin 17 (Select Input) and pin 16 (Initialize Printer) to 1.
2. Check that the KFC15/KFCD15’s pin 11 (Busy) is set to 0.
3. Place data on the data lines.
4. Set pin 1 (Strobe) to 0 then 1.