IBM LPFK reverse engineering

[Michael B. Brutman]

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 ...


Mike


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 
> LPFK:
> 
>   __   __
>  /  |_|  \
> | 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)
> 
> Thanks.