IBM LPFK reverse engineering
Michael B. Brutman
mbbrutman-cctalk at brutman.com
Sun Aug 17 19:48:37 CDT 2008
I downloaded Realterm - that was a good tip.
I'm on a real serial port (no USB involved) and I still can't make it
reset or do anything. However, I did discover that it will respond with
Hex 0x03 (single char, ASCII 3) if I hit Ctrl-F.
I will compare your pinouts to my notes after dinner ...
Philip Pemberton wrote:
> Michael B. Brutman wrote:
>> I've been banging my head on this on and off for over a year. Phil
>> has made me feel a little better by verifying what I was hitting.
> Ouch! Bet it took a lot of aspirin to get rid of THAT headache!
>> Phil - I'm on Linux using MINICOM or DOS using an old PROCOMM.
>> Sending a break while doesn't seem to have any effect. How long is
>> the break being held for? (PROCOMM is configurable.)
> 500 milliseconds according to Realterm. The signal is going via a
> USB-serial adapter (FTDI TTL-232R) and into a MAX232, then on to the LPFK.
>> Also, you say you are using 9600 O81 for the protocol? That is
>> different than the Code Ninja page, which says 9600 N81. Can you give
>> me all of the parameters so I can at least reproduce the reset that
>> you managed to trigger?
> Baud rate: 9600
> Parity: Odd
> Data bits: 8
> Stop bits: 1
> Hardware Flow Control: Off
> Sending SFFFFFFFF\n (SFFFFFFFF followed by a Line Feed) caused the LEDs
> to blink quickly then turn off again
> Also try connecting RXD to ground.
> As regards pinouts, this is what I've got for the 8-pin connector at the
> __ __
> / |_| \
> | 8 7 6 |
> | 5 4 3 |
> \ 2 1 /
> PCB pads:
> [ 33uF ]==:
> o---[ R ]---o
> 8 7 6 5 4 3 2 1
> Pinouts are:
> 1 GND
> 2 GND
> 3 VCC (+5V)
> 4 RxD (INPUT TO LPFK)
> 5 TxD (OUTPUT FROM LPFK)
> 6 PUR (Pullup resistor -- or something?)
> 7 NC (no connection)
> 8 NC (no connection)
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