Keyboard Controller - DTK Apex 386/33 User Manual

Keyboard Controller

The keyboard controller is based on the 8042(U128) single-chip
microprocessor and is used to support the PEM-3301 keyboard inter-
face. The keyboard controller performs the following functions:
The keyboard controller has two 8-bit ports. One of them serves as an
input port, while the other serves as an output port. Besides these,
there are two test inputs. One of them, namely TEST0, is used to
monitor the state of the clock line, while the other, namely TEST1, is
used to read the state of the keyboard's data line.
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Chapter 6: Appendix
Receives serial data from keyboard, checks parity, trans-
lates it into a system scan code, if necessary, transfers data
to the data buffer and interrupts the processor.
Executes system commands, places the results in the data
buffer and interrupts the processor if necessary.
Transmits the system data in the data buffer to the keyboard
in the serial format along with the parity bit. Reports the
response of the keyboard to the system.
Reports errors to the system through the status register.
Input Port Bit
Pin 27 - Bit 0
Pin 28 - Bit 1
Pin 29 - Bit 2
Pin 30 - Bit 3
Pin 31 - Bit 4
Pin 32 - Bit 5
Pin 33 - Bit 6
Pin 34 - Bit 7
Definition
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Keyboard Inhibit Switch
0 Inhibited
1 Not inhibited