W65C265SXB

[BitWise]

In a moment of weakness I decided to try one of these boards out as well.

Looks much easier to add extra SRAM to this board. The chip provides chip selects for some external banks and full 24 bit address. It runs slower so I can use some of my 55nS 512K RAMs with it.

Four UARTs + the USB makes it easy to connect to serially and the UARTs support a faster 56K baud. Not as much I/O capability as the microprocessor boards but I don't think I need that much.

[scotws]

Do we know if these UARTs have the same bug as the 6551 as a chip? And I note that Mouser.de has the price at €100 -- yikes! Can that be right?

EDIT: Scratch that, just found your other thread. Sorry, I'd somehow missed that.

[BitWise]

Completely different UART design. Should not have the same bug.

My board has arrived intact. Rubber feet added. Time for a test drive.

[scotws]

BitWise wrote:

Completely different UART design. Should not have the same bug.

Ah, now that is very interesting. Looking forward to hearing how this turns out.

[BitWise]

The slower clock speed on the W65C265SXB makes it much easier to play with the hardware. I couldn't find my 512K SRAMs but I did turn up a 128K so I added it using jumper wires and a breadboard. Should be plenty to play with until I locate the bigger chips.

Loads of wires

This shows the connections.

128K SRAM Expansion

I have some spare 128K Flash EEPROMs I got to backup the W65C816SXB firmware so I'm going to populate the empty ROM socket as well.

[handyandy]

Hi Bitwise,

I would ask if you've looked at the tone generator firmware source (file: R_TONES.ASM page 109 265romlist file) and if it's the same on the sxb board rom. There would appear to be a bug if routine is entered with a number in accumulator larger than 3 a crash would happen. Routine is entered with pha, phd, phb and on error exits pla sec rtl. Code would start @ 00:$f423 - 00: $f441 according to source code list but may have moved if rom had been reassembled since 1995-2000. There is a jump table
and CONTROL_TONES is located at 00:$e009(?).

Regards,
Andy

[BitWise]

handyandy wrote:

Hi Bitwise,

I would ask if you've looked at the tone generator firmware source (file: R_TONES.ASM page 109 265romlist file) and if it's the same on the sxb board rom. There would appear to be a bug if routine is entered with a number in accumulator larger than 3 a crash would happen. Routine is entered with pha, phd, phb and on error exits pla sec rtl. Code would start @ 00:$f423 - 00: $f441 according to source code list but may have moved if rom had been reassembled since 1995-2000. There is a jump table
and CONTROL_TONES is located at 00:$e009(?).

Regards,
Andy

I've not looked at it before but you're right compared, it looks like the routine fails to pull DBR and DP off the stack before returning when the argument is invalid.

If you execute AND #$03 before calling the routine it should always work.

The monitor on my SXB has the same assembly date and time as the listing so it looks like the mask ROM in the W65C265 chips hasn't been updated in 10 years and the bug will be in all of them.

[BitWise]

I've started a port of my SXB hacker code to the 65C265. The basic commands and XMODEM appear to be working but erasing and loading into the flash ROM needs some more work.

First cut of the source files are on Github here https://github.com/andrew-jacobs/w65c265sxb-hacker.

I'm rearranging the code and adding some conditional bits so that the 65C816 and 65C265 will use a common module for the commands with hardware related bits in a separate module. Its a work in progress at the moment.

[BitWise]

No longer a big mess of wires. 2x 512K of SRAM on a daughter board.

[handyandy]

While browsing I came across this: http://wdc65xx.com/gettingstarted/ and it says that the 265sxb can be powered and interfaced with an android smartphone. Is there an app for that?

Regards,
Andy

[BitWise]

handyandy wrote:

While browsing I came across this: http://wdc65xx.com/gettingstarted/ and it says that the 265sxb can be powered and interfaced with an android smartphone. Is there an app for that?

Regards,
Andy

I guess you just need the right USB cable and a serial terminal application.

[porcupine]

Nice work on the daughter board, I have an EagleCAD schematic and layout for a similar board with 4 x 512KB SRAM and 512KB of flash, but never finished it.

What did you use for layout? I'm curious about positioning of the header, etc.

I have written a Python class for communicating with the firmware for doing uploads of code and the like for non-Windows folks. I used that combined with a Makefile that can assembly code in ca65 and then upload it to the system to execute. I will try to clean it up and get it up on github or similar.

[BitWise]

porcupine wrote:

What did you use for layout? I'm curious about positioning of the header, etc.

That board was done with DesignSpark, the free PCB design tool from RS components.

[Alamorobotics]

That is really awesome...

Would a similar memory board work for W65C816SXB as well ?
Do you have any plans of designing one for W65C816SXB ?

[scotws]

Well, you convinced me. Just ordered one, including a bunch of Flash ROMs. Me thinks this should be the quickest way to get a 65816 system up for testing my assembler and emulator and stuff. Will post in this thread once I get it up and running.