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+++
title = "IMC-2001 keyboard"
+++
connector to machine (sort of a rubber version of a DB-9):
The connector on the computer side has a 9-pin DSUB connector male:
```
+----------- white INTR
| +--------- black GND
| | +------- green DATA
| | | +----- blue RESET
| | | | +--- Yellow CLOCK
-------------
\ O O O O O /
\ O O O O /
---------
| | | +---- red 5V
| | +------ n.c.
| +-------- n.c.
+---------- n.c.
```
On the keyboard PCB there is a strange white connector with the following layout:
```
+------------- white INTR (active low, after last clock tick)
| +----------- black GND
| | +--------- blue RESET (active low)
| | | +------- green DATA
| | | | +----- yellow CLOCK
| | | | | +--- red +5V
+-----------+
|o o o o o o|
+-----------+
| |
```
Keyboard layout:
{{< figure src="/images/hardware/imc-2001/keyboard_front.jpg" alt="keyboard layout" >}}
Keyboard has a 8039 CPU inside and a 2K EPROM:
{{< figure src="/images/hardware/imc-2001/keyboard_pcb_controller_prom.jpg" alt="PCB and controller" >}}
On the oscilloscope:
{{< figure src="/images/hardware/imc-2001/oscilloscope_serial_keyboard.jpg" alt="serial keyboard signal" >}}
The protocol is basically ASCII over 19200 baud serial, with an interesting end signal which
IMHO triggers a latch on the motherboard or so (INTR white above).
Broken keyboard cable (the black pins are just connectors added by me to test connectivity,
both connector are female per default):
{{< figure src="/images/hardware/imc-2001/keyboard_cable.jpg" alt="PCB and controller" >}}
|
