I thought this might be of interest to everyone who is interested in
programming their I/O Extender directly.
This information comes directly from GVP technical support.
* * *
DEVELOPER INFO
Many users have expressed an interest in developing I/O Extender drivers
for specific applications. While GVP Technical Support does not have
access to any developer information, this is the total of the information
we have been able to gather. This information is being provided as a
service to our users. It is not supported by GVP and is provided "AS IS".
We hope this is sufficient for programming to the board.
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THE I/O EXTENDER USES THE STARTECH ST16C552 CHIP. INFORMATION ON THIS CHIP
SHOULD BE AVAILABLE FROM YOUR LIBRARY OR BY CONTACTING STARTECH DIRECTLY.
TECHNICAL SUPPORT DOES NOT HAVE A NUMBER FOR STARTECH. THE ORDER NUMBER IS
ST16C552CJ68.
THE GVPIO DRIVER FOLLOWS THE SAME COMMAND SET AS THE STANDARD AMIGA SERIAL
AND PARALLEL DRIVERS. IF YOUR PROGRAM MAKES CALLS TO THE DRIVER, YOU
SHOULD ONLY HAVE TO SUBSTITUTE THE GVP DEVICE NAME FOR THE AMIGA DEVICE
NAME (I.E. GS0: FOR SER:).
THE FOLLOWING IS SPECIFIC INFORMATION ON THE I/O EXTENDER BOARD:
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MEMORY MAP:
BOARD ADDRESS = $Ex0000
SERIAL PORT 0 REGISTERS = $Ex0160 - $Ex016E
SERIAL PORT 1 REGISTERS = $Ex0260 - $Ex026E
PARALLEL PORT REGISTERS = $Ex0360 - $Ex0364
*ON-BOARD CONTROL REGISTER (READ AND WRITE) = $EX0460
CONTROL REGISTER BREAKDOWN:
BIT
(0)** - PORT 0 MIDI SELECT => 0 = DRIVERS, 1 = MIDI
(1)** - PORT 1 MIDI SELECT
(2) - PORT 0 DRIVER SELECT => 0 = RS232, 1 = OPTION HEADER
(3) - PORT 1 DRIVER SELECT
(4) - INTERRUPT SELECT => 0 = INT2, 1 = INT6
(5) - ROM BANK SELECT => 0 = LOW 32K BANK, 1 = HIGH 32K BANK
(6) - PORT 0 HANDSHAKE => 0 = RTSx OR RXRDYx, 1 = RTSx ONLY
(7) - PORT 1 HANDSHAKE
* THE CONTROL REGISTER POWERS UP IN AN UNKNOWN STATE AND MUST BE SET
BEFORE USING.
** BITS 0 AND 1 ARE HIGHER PRIORITY THAN BITS 2 AND 3. THEREFORE, WHEN
IN MIDI MODE, DRIVER SELECTION IS "DON'T CARE".
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