Updates

03 Jun 2023

Added .DSK image of original (and long sought after) MSX CP/M 2.2 boot disk (MSXCPM.DSK 720K)

MSX Network

• Дополнительные команды BASIC, ч.1
• Дополнительные команды BASIC, ч.2
• Описание MSX NET-BIOS
• Текстовое описание MSX NET-BIOS
• Частично дизассемблированный NET-BIOS, местами даже с комментариями
• CP/M stuff
• Network module schematics, page 2
• МИДИ\сеть2 Веpсия 1.16
• YM3802 abstract, datasheet
• NetTools

MSX-Link

This project's main goal was to have my diskless MSX2 (Yamaha YIS-503/IIIR) hooked to a PC that would emulate (well, actually simulate) another MSX2 machine, and with quite a bit of reverse engineering, programming, hacking and soldering to be able to download games using YIS-503/IIIR's built-in networking capabilities.

This simple circut allows any MSX equipped with Network Module to be connected to any RS-232 port. Full opto-coupling (both TX and RX), no additional power supply (necessary voltages taken from MSX and RS-232). Schematics (JPG, 68K) PCB design (PostScript, 51K) Components layout (PostScript, 83K) Communicate using speed 38400, 8 bits and 2 (!) stopbits. At least it works for me this way.

Packet formats

Typical packet has a header, a payload, sometimes a checksum and terminator (0x97 if there will be more packets, 83 if this is the last packet in a sequence).

HEADER					PAYLOAD		CHECKSUM	TERMINATOR
F0 00	Destination address	Packet type	Source address	Command (2 bytes - see Encoding)	Optional parameters (encoded)	Optional data byte(s) (encoded)	16-bit checksum (encoded)	97 (intermediate packet) 83 (last packet)

Header

Source and destination address can be 00 (Teacher), 01..0F (Student), and 7F (Broadcast).

Command - see Packet 0x01 description.

Payload

Maximum data bytes (without optional parameters) - 58 bytes.

Checksum

Checksum is a 16-bit sum of all bytes in payload. Packets with wrong checksum are silently discarded.

Encoding

Each 8-bit byte is sent as a pair of 7-bit octets, with the first octet carrying only bit 7 of original byte, and the second carries bits 6..0. This allows for sending packets across MIDI-like network (and through YM3802 chip in particular) in accordance with MIDI standards.

Example: byte 21 is sent as 00 21; byte FF is sent as 01 7F.

There are four types of packets used in MSX network.

Packet 0x01

This is the Base type of packet. Each Base packet should be acknowledged with ACK (0x06) packet, except for specific ones (see table).

00

01

02

03

04

05

06

07

08

09

0A

0B

0c

0d

0e

0f

10

11

12

13

14

15

16

17

18

19

1a

F0

00

ADR2

01

ADR1

00

CMND

CP/M

20 NET-CLOSE-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

21 NET-SEARCH-FIRST

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

22 NET-SEARCH-NEXT

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

23 NET-DELETE-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

24 NET-READ-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

25 NET-WRITE-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

26 NET-CREATE-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

27 NET-RENAME-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

2c Master Data (first packet)

2d Master Data (subsequent packets)

2e NET-SEARCH-END

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

2f NET-OPEN-FILE

LNGTH

H

F

A

FCB (37 bytes)

CHKSUM

83

30 re: NET-CLOSE-FILE

31 re: NET-SEARCH-FIRST

32 re: NET-SEARCH-NEXT

33 re: NET-DELETE-FILE

34 re: NET-READ-FILE

35 re: NET-WRITE-FILE

36 re: NET-CREATE-FILE

37 re: NET-RENAME-FILE

3c Slave Data (first packet)

3d Slave Data (subsequent packets)

3e re: NET-SEARCH-END

3f re: NET-OPEN-FILE

General

40 SEND

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

41 SEND

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

42 SHEX (data packets)

43 SHEXS (data packets)

44 SEND-VRAM-DATA

45 SHEXS (file data packets)

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

46 MESS, TALK

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

47

48 SNDCMD

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

49 SNDM (first packet)

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

4a SNDM (subsequent packets)

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

4b re:RECV

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

4c re:RHEX

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

4d re:RHEXS data

4e re:RHEXS (file)

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

4f re:63

50

51 re:RCVM

LNGTH

byte 1

byte 2

bytes NN

CHKSUM

97/83

52 SHEX/SHEXS

START

END

83

53 SEND-VRAM-REG

START

END

V_REGDAT (40 bytes)

83

54 re:RHEXS header

START

END

V_REGDAT (40 bytes)

83

55 SHEXS (file)

START

END

83

56 re:RECEIVE-VRAM-REG

START

END

V_REGDAT (40 bytes)

83

57 RHEX

START

END

83

Respond with 4c

58 RHEXS (mem)

START

END

83

Respond with 54, then send 4d(s)

59 RECEIVE-VRAM-REG

START

END

83

Respond with 56

5a RECEIVE-VRAM-DATA

START

END

83

Respond with 4e

5b RHEXS (file)

START

END

83

Respond with 4e

5c POKE

ADDR

byte 1

83

5d POKE (NetRAM)

ADDR

byte 1

83

5e RUN

ADDR

83

5f PEEK

ADDR

83

Respond with 61

60 PEEK (NetRAM)

ADDR

83

Respond with 61

61 re:PEEK

byte 1

83

62 RECV

01 7F 01 7F

01 7F 01 7F

83

Respond with 4b

63

83

Respond with 4f

64 RCVM

83

Respond with 51

65 STOP

83

Packet 0x15 (PING)

Ping packet type. Every workstation upon receiving of this packet should respond with 0x05 (PONG) packet.

00	01	02	03	04	05	06
F0	00	ADR2	15	ADR1	O_STATUS	83

Master workstation sends PING to all Slave workstations in turn (01..0F) when idle, to keep list of active Slaves up to date.

Example: MASTER SLAVE 15 PING 05 PONG

Packet 0x06 (ACK)

This packet is used to acknowledge the reception of most Base packets.

00	01	02	03	04	05	06	07	08	09	0a	0b
F0	00	ADR2	06	ADR1	U_STATUS						83

Example: MASTER SLAVE 5c POKE 06 ACK

Packet 0x05 (PONG)

Response to PING (0x15) packet.

00	01	02	03	04	05
F0	00	ADR2	05	ADR1	83

Sending files from PC

MS-DOS executable: msx-link.exe (500K)

Source: https://github.com/mr-GreyWolf/MSX-Network