[Premium-Rx] Racal A6A1 Board Setup Help Needed

[Guy Atkins]

Hi Claus,

Thanks for taking the time to look up this information. I knew that my
receiver has the GM CPU board with the 3 EPROMs, and I just verified that
the remote board is also a GM model with the IM6402 UART.

So, I have the correct combination of boards, but unfortunately my manuals
cover the GM-3 version.

Could you tell me what your GM manual says is the normal serial protocol? Is
it the common 8-N-1, or maybe "1 start bit, 7 data bits, a parity bit, and 2
stop bits" such as the GM-3 manual states?

Thank you,

Guy

-----Original Message-----
From: Claus Hanke [mailto:claushanke at yahoo.com]
Sent: Sunday, February 22, 2004 9:28 PM
To: Guy Atkins
Cc: Premium-Rx
Subject: Re: [Premium-Rx] Racal A6A1 Board Setup Help Needed


Hi Guy,
I checked both manuals, GM and GM-3, and it is not possible to mix the
boards.
So, if you have a remote for the GM-3 (UART 8251) you cannot use it with the
GM CPU board (3 EPROMs and 3850 CPU). The pining between the boards
 used by the GM and GM-3 versions are different. The GM-3 CPU is a Z80
(1 EPROM). The UART on the GM remote board is a IM6402 or compatible.
That would explain that the receiver is not working anymore. Pin 2 - GM is
the
RESET (active low) and MI (active low) for GM-3. I'm just guessing, but
maybe
the CPU is always in RESET mode.
Anyhow the two versions are not compatible, so check what versions you have.
Hope that helps.
Claus