W65C02SXB 65C51 Header -> Null Modem Cable

[Johnny Starr]

Hello all, its been a long time since I posted something. I recently picked up one of these guys: https://wdc65xx.com/Single-Board-Computers/w65c02sxb/
I'm not much of a hardware guy I'l have to admit. So, I wanted something that had real hardware that I could write my software for. So far, the WDCDB (debugger/monitor) has been splendid and worked flawlessly.

However, since I am writing my own BASIC and FORTH interpreters, I would like to be able to connect to this board over a terminal connection. The 65C51 onboard has a jumper with the following pins:

I know that RXD/TXD and ground are required, but I'm not sure about the other pins. What I'd like to go with is a null modem DB9, and just purchase a DB9 serial -> USB cable of some sort. Some of the schematics I've seen make use of the MAX232 chip.
I'm hoping that this isn't required. I was a little disappointed that I couldn't just use the microUSB "TIDE" connector to connect to the device. I'm hoping that someone out there has played with this board and knows exactly what I need to do

Finally, here's the code that sets up the ACIA

Code: Select all

ACIA_BASE       equ     $7F80
ACIA_DATA       equ     ACIA_BASE
ACIA_STATUS     equ     ACIA_BASE+1
ACIA_COMMAND    equ     ACIA_BASE+2
ACIA_CONTROL    equ     ACIA_BASE+3

        org     $300
START:
        lda     #%00001011      ; no parity
        sta     ACIA_COMMAND
        lda     #%00011111      ; 1 stop bit, 8 data bits, 19200 baud
        sta     ACIA_CONTROL

Thanks!

[BitWise]

It is possible to usurp control of the USB serial connection but you lose the ability to use the WDC software at the same time.

As for the ACIA connect a jumper wire between RTS and CTS. I use USB serial adaptors connected to RX, TX and GND. I have a load of (cloned) pl2303 serial modules which can be made to work as long as you use an old windows driver. A safer bet is a newer FTDI 232RL based adapter.

[Johnny Starr]

So, maybe if i went with something like this https://www.amazon.com/Adapter-Serial-C ... B075N82CDL
Would I just be able to run dupont connector wires to the appropriate pins?

[BitWise]

Yes that should work. You could connect rts and cts for hardware flow control with that board.

[floobydust]

One other thing to be aware of is the current WDC W65C51 parts have an issue with the transmit bit being stuck on in the status register. It's been heavily discussed here and there have been some workarounds for it.

Take a look at this thread for the details: viewtopic.php?f=4&t=2543

Page 2 shows the discovery and confirmation of the hardware defect... and goes on.