This repository includes two tools. The first, sxb is for interacting with the W65C02SXB board by Western Design Center (WDC). The second, sxb6 is for the WDC W65C816SXB board with WDCMON v2.0.

Note the W65C02SXB likely WDCMON v2.0.4.3 which has a different api than the WDCMON v2.0 on the W65C816SXB board.

The ROM in my W65C02SXB board starts with this information:

00000000  57 44 43 ff 4c 15 81 ff  57 44 43 36 35 63 30 32  |WDC.L...WDC65c02|
00000010  53 4b 20 57 44 43 4d 4f  4e 20 56 65 72 73 69 6f  |SK WDCMON Versio|
00000020  6e 20 3d 20 20 32 2e 30  2e 34 2e 33 56 65 72 73  |n =  2.0.4.3Vers|
00000030  69 6f 6e 20 44 61 74 65  20 3d 20 54 75 65 20 4a  |ion Date = Tue J|
00000040  75 6c 20 20 32 20 32 30  31 33 20 31 36 3a 32 34  |ul  2 2013 16:24|

Note the ROM says WDC65C02SK, not W65C02SXB as might be expected. Regardless this version works with the original sxb tool by kalj and others.

The ROM in my W65C816SXB doesn't have the same block of text, but does have SXB6 embedded near the beginning. The SXB6 value and some version information is returned by the board info call.

The start of the ROM file looks like below. I change the code bytes to 'xx' as we are only interested in the 12 bytes returned by the board info call. The first 4 bytes are 'SXB6' to identify the board, followed by a 32 bit little endian hardware version and then a software version. In this case my hardware is revision 300 and software is 200. This should correspond to v3.0.0 hardware (Rev C on the silkscreen on mine) and WDCMON v2.0.

00000000  xx xx xx xx xx xx xx xx  xx xx xx xx 53 58 42 36  |............SXB6|
00000010  2c 01 00 00 c8 00 00 00  xx xx xx xx xx xx xx xx  |,...............|

Of course getting the ROM information above generally means you already ran the sxb or sxb6 tool, but I put it here for confirmation / clarification.

Since the versions of WDCMON are quite different, I just copied the original sxb tool to sxb6 (the board identifier in the ROM) and made the modifications to support it.

These two scripts should probably be merged with a flag to select the board type. That is a future enhancement I'll look at once I'm confident in SXB6 support.

You'll need python3 with the pyserial package installed.

You can show supported commands with the -h option. Currently only info, read, write, and exec are supported. None of the flash commands are implemented.

$ ./sxb6 -h
usage: sxb6 [-h] [-d DEVICE] command ...

positional arguments:
  command
    info                Get board info
    read                Read bytes
    write               Write bytes
    exec                Start execution

options:
  -h, --help            show this help message and exit
  -d DEVICE, --device DEVICE
                        Serial device

You'll need to pass the device to use, or you could edit the script and change the default line. (Look for CHANGEME)

Under Linux for example you could run sxb6 -d /dev/ttyUSB0 info to get the board info.

The info command prints the board model. This should be SXB6 for the W65C816SXB board. If/when the W65C02SXB (with WDCMON v2.0) is supported it might be different.

Here you can see my board is SXB6, the board revision shows as 300 (my board is a REV.C) which I think would be 3.0.0. The software / monitor version of 200 should be equivalent to 2.0.0 here.

$ ./sxb -d /dev/tty.usbserial-3 info
     Board model: SXB6
  Board revision: 300
Monitor revision: 200
00  53  S
01  58  X
02  42  B
03  36  6
04  2c  ,
05  01
06  00
07  00
08  c8  È
09  00
0a  00
0b  00

The read command returns size bytes starting with address addr and dumps them raw to stdout. If you pass the --table option it will dump in hex bytes similar to the hexdump command.

$ ./sxb6 read -h
usage: sxb6 read [-h] [-t] addr size

positional arguments:
  addr
  size

options:
  -h, --help   show this help message and exit
  -t, --table

The command below will dump the WDCMON ROM image itself.

$ ./sxb6 -d /dev/tty.usbserial-3 read 0xf800 2048 > wdcmon.bin

Using the --table argument generates a nice table as shown here.

$ ./sxb6 -d /dev/tty.usbserial-3 read --table 0xf800 64
 addr |  0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
 ------------------------------------------------------
 f800 | 4c e6 f9 4c f4 f9 4c 18 fa 4c 34 fa 53 58 42 36
 f810 | 2c 01 00 00 c8 00 00 00 18 fb 78 c2 10 e2 20 a2
 f820 | ff 07 9a a9 00 eb a9 04 85 10 a9 00 9c a1 7f a9
 f830 | ff 8d a0 7f a9 04 8d a1 7f 9c a0 7f 38 6e a0 7f

With the write command you can load a file into SRAM starting at a specific address.

$ ./sxb6 -d /dev/tty.usbserial-3 write 0x2000 demo.bin

The exec command executes code by pushing the address to the stack and using rti to call the address provided. The WDCMON command loop is setup as the return address so if you use rts from your code it should return to the monitor.

$ ./sxb6 -d /dev/tty.usbserial-3 exec 0x2000

Forked from the excellent work here: https://github.com/kalj/sxb

With some patches posted to an issue: kalj#1

Original credits listed by kalj: Inspired by https://github.com/andrew-jacobs/dev65 / https://github.com/andrew-jacobs/w65c02sxb-monitor and the python script by forum.6502.org user cjb (see http://forum.6502.org/viewtopic.php?f=4&t=5698).