Trying to dump Yamaha SKW-01 | MSX Resource Center (صفحة 4/6)

Master (159)

16-01-2023, 10:33

I have MSX Yamaha CX11 with SKW-01 and printer cable. The manuals for the CX11 and SKW-01 are included. All items are in excellent shape for sale. The link is here:

MSX Yamaha CX11 for Sale

بواسطة sdsnatcher73

Prophet (3954)

16-01-2023, 17:45

acet wrote:

dump tool
https://github.com/uniabis/msxrawl/tree/main/dumpskw1

PORT0 0000-7FFF:32KB jis1 kanji font(1/4),8000-FFFF:mirror
PORT1 0000-7FFF:32KB jis1 kanji font(2/4),8000-FFFF:mirror
PORT2 0000-7FFF:32KB jis1 kanji font(3/4),8000-FFFF:mirror
PORT3 0000-7FFF:32KB jis1 kanji font(4/4),8000-FFFF:mirror
PORT4 0000-7FFF:32KB EXTRA ROM,8000-87FF:2KB SRAM,8800-FFFF:SRAM mirror

The tool reports skw not fount. I suspect it does not search subslots (using a CX-7M, the module slot is in 3-3).

بواسطة sdsnatcher73

Prophet (3954)

16-01-2023, 18:14

Dump worked on CX11 (which has module slot in primary slot ): SKW-01.ZIP

6a7f41d89f9d50f4ff648233670660cfb07a41ee SKW-01.ROM
5ac6115c6db65b9b98ecfc329ed08dc06a92a6d7 SKW-01.SRM
f0901a63de6c95a42ce6ad82dd5e6bfba4bcf180 SKW-01KF.ROM
82f2ecd9f3135a8602d54cc6322216b3b15ae8b3 SKW-01P4.ROM

BTW there is a battery ON/OFF switch on the module, it is set to OFF dusring the dump so the SRAM content is likely initialized by the ROM.

بواسطة Manuel

Ascended (19465)

17-01-2023, 13:09

I'll try to look at it soon, thanks!

بواسطة Manuel

Ascended (19465)

17-01-2023, 20:43

It might be me, but I'm missing some information on how it works.
1. what is the initial memory map?
2. how exactly does it work to read data from the kanji ROM?
basically, it's not clear to me how it works at all... what is switched with which write to these values?

@acet??

بواسطة acet

Supporter (12)

18-01-2023, 03:16

MAIN ROM(SKW-01.ROM) is mapped to 0000-7FFFh(excluding memory mapped I/O) of slot without selection of bank nor mirror.
Memory mapped I/O is mapped to 7FC0-7FCFh of slot without mirror.

PORT0-3(BUFFERED) INITIAL VALUE

ADDRESS H : unknown
ADDRESS L : unknown
READBUF: FFh
STATUS: 00h(NOT READY)

PORT4(UNBUFFERED) INITIAL VALUE

ADDRESS H : 00h?
ADDRESS L : 00h?
DATA: B1h(same as first byte of SKW-01P4.ROM)

PORT 0-3(BUFFERED) READ CODE

;DE address to read
;HL memory mapped I/O base address(7FC0,7FC2,7FC4,7FC6)
L408A:
 LD (HL),E ; set low address, and become not ready, value of READBUF is not affected
 INC HL
 LD (HL),D ; set high address, and start reading from ROM to READBUF
 DEC HL
WAIT:
 BIT 0,(HL) ; dummy read status
 BIT 0,(HL) ; read status
 JR Z,WAIT ; loop until ready for read(value of status will change to 01h from 00h)
 INC HL
 LD A,(HL) ; read value of READBUF

بواسطة Manuel

Ascended (19465)

18-01-2023, 09:10

So, if I understand correctly (please confirm or correct):
1. Main ROM is always visible in Z80 space 0-7FFF, except on the places where there is the memory mapped I/O.
2. In Z80 space 8000-FFFF nothing is visible (0xFF). The memory mapped I/O ports are not visible there either.
3. With PORT0 (7FC0-7FC1), the first 32kB of the kanji font ROM can be read. The MSB of the 16-bit input address is ignored.
4. With PORT1 (7FC2-7FC3), the second 32kB of the kanji font ROM can be read. The MSB of the 16-bit input address is ignored.
5. With PORT2 (7FC4-7FC5), the third 32kB of the kanji font ROM can be read. The MSB of the 16-bit input address is ignored.
6. With PORT3 (7FC6-7FC7), the fourth 32kB of the kanji font ROM can be read. The MSB of the 16-bit input address is ignored.
7. With PORT4 (7FC8-7FCB), the "special" 32kB ROM and SRAM can be read (and written for the 2kB SRAM). The MSB of the 16-bit input address is used to select between ROM and SRAM. For writing, when ROM is selected, nothing happens, when SRAM is selected, the 2kB SRAM is written. For the SRAM address, only the lowest 12-bits are used.
8 The "special" 32kB ROM is never mapped directly into Z80 address space.

بواسطة acet

Supporter (12)

18-01-2023, 10:03

All correct, but writing to port 4 "special" 32kB ROM has not been tested if it affects SRAM.

بواسطة Manuel

Ascended (19465)

18-01-2023, 11:07

OK, let's assume it does not. As for the printer port, can we assume it's working exactly as a normal MSX printer port, but instead it uses that memory mapped I/O?

I've implemented a first prototype and it seems to work pretty well

But I'll need help from owners of the real thing or people who can read Japanese to be sure.

Here's a small demo: https://youtu.be/YLktAtin5Kg

بواسطة acet

Supporter (12)

18-01-2023, 11:43

The movie seems to display only symbols on port 0.