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6. JAMMA Video Standard - SEGA Modiciations


This page assumes you have read the documentation regarding the JAMMA video standard. If you have not, it is recommended to read that first.

6.1 Packet framing

Request packet (master->slave)
00 01 02 03 04 05 06 07
E0h n Dest Seq CMD D0 D1 D2 Dn-5 SUM
Response packet (slave->master)
00 01 02 03 04 05 06 07 08 09
E0h n Src Seq Status CMD Report D0 D1 D2 Dn-7 SUM

6.2 Commands and responses

Response packets of this format include a source address, which should match the destination in the request. The sequence number of both the request and response should be the same (? todo: verify this), and should be modulo 32 (20h).

While the packet format would suggest it supports multiple commands, I have never observed more than a single command per packet. Response packets include the command number between their packet status and report status bytes.

6.3 Individual commands

The following is a reference table for communication with an 838-14971. Endpoints required for MIFARE cards are marked with M, FeliCa F, and LEDs L.

Req Name Code Description Request Size Response Size
MF Get Firmware Version 30 Retrive the firmware version string 0 1+
MF Get Hardware Version 32 Retrive the hardware version string 0 1+
MF Radio On 40 Enable the NFC radio 2 0
MF Radio Off 41 Disable the NFC radio 0
MF Poll 42 Retreive a list of NFC devices 0 3+
M Select MIFARE tag 43 1+ 0
44 1+
MF Set MIFARE Classic key 50 Provide the key used for MIFARE decryption 1+ 0
51 Read back the MIFARE key 1+ 6
M Read MIFARE block 52 Read a secified block from a MIFARE Classic device
MF Set Aime key?? 54 /shrug 1+ 0
55 Read back the Aime key 6
MFL Reset 62 Reset the device to an initial state 0
F FeliCa communication 72 Proxy the enframed command to a present FeliCa device Variable Variable
LED commands (address 08)
L Reset 10
Set timeout 11
Set timeout response 14
L Set LED colour 82
Set LED count 86
L Get board info f0
Get board status f1
Get firmware sum f2
Get protocol version f3
Bootloader fd