Pinout – Mazda 5 audiosysteem

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 Mazda Radio connector 24 pins

Mazda radio connector 24pins

Mazda radio connector 16pin pinout

mazda 5 model 2006 radio connectors

Bronnen:

Link #1 / Link #2 / Link #3


BUS onderkant v/d radio

Bron

Pinout:

Pin Function
1 Bus data (+5v TTL)
2 Bus ground
3/4 Power (+12v)
5/6 Power ground
7 Eject
8 Not connected
9 Text – Cl(ock?)
10 Text – Do(?)
11 ACC (+12v)
12 SMUTE
13 Right channel audio
14 Audio ground
15 Left channel audio

Bus data

I’ve used my Risc PC’s parallel port to watch the data exchanged between the main unit and the CD deck. A simple bit of ARM code samples roughly 1MB of data a second for about 4 seconds and writes it to disk. This data is then analysed by a small BASIC program to produce oscilloscope-like traces. Using this method, I’ve been able to determine some patterns to the data on the bus.

As you can see, the pulses seem to be evenly spaced, with the longer pulses indicating a binary 1 and a shorter pulse indicating a binary 0. There always seems to be an even multiple of 4 pulses, so the protocol seems to work with nybbles rather than full bytes. The bus is pulled up to 5v and the pulses are 0v. The traces are inverted to make reading them easier. Timing-wise, each 0 pulse seems to be about .5ms and each 1 pulse seems to be about 1.7ms. The pulse plus gap is about 3ms in both cases. Given this, we can transcribe the traces above as follows:

The next action I traced was switching from the radio to the CD deck with a CD in:

Some messages from track 2, with the fast-forward button pressed half-way through:

And some track seeking:

From these traces, and in conjunction with watching the LCD display, I’ve made some headway into decoding the protocol. It was quite difficult to figure out the checksum method for the messages!

Message Protocol

The bus message protocol seems to be a nybble based system with a minimum message length of 3 nybbles (or 12 bits). Every message is of the following format:

Purpose Length (bits) Notes
Module 4 0000 = Tape deck
0011 = CD deck
0101 = CD changer (external)
0110 = CD changer (upper module)
0111 = MD deck
1001 = Base unit
1010 = MP3 CD deck
Command 4
Message data any Message specific
Checksum 4 To calculate the checksum, take all the nybbles (excluding the checksum itself, obviously) and xor them all together. Add 1 and ignore any overflow. This gives the checksum value.

Messages sent to modules:

Command Data Length (bits) Purpose Data Format
0001 16 or 20 Control
Subcommand Data
0001 xxxx-yyyy-0010
where xxxx-yyyy is:
0000-0001 for play
0000-0100 for ff
0000-1000 for rew
0110-0000 for stop
0011 0000-aaaa-bbbb-0001
where a-b is the track to seek to
0100
Configure
Set configuration data abcd-efgh-ijkl-mnop
where:
b is repeat
g is random
1000 0 Anybody home? No data
1001 0 Wake up No data

Messages sent by the CD module:

Command Data Length (bits) Purpose Data Format
1000 4 0001 – sent after connecting power
1001 52 Status aaaa-bbbb-bbbb-cccc-dddd-eeee-eeee-ffff-ffff-gggg-hhhh-iiii-jjjj
where:
aaaa is 0000 (stopped), 0110 (fast forwarding), 0100 (playing), 0101 (seeking), 0111 (rewinding)
bbbb-bbbb is a BCD encoding of the current track
cccc-dddd is 0000-0001 (maybe CD number in a changer?)
eeee-eeee is a BCD encoding of the current position minutes
ffff-ffff is a BCD encoding of the current position seconds
gggg is 0100 when repeat is on, 0000 otherwise
hhhh is 0010 when random is on, 0000 otherwise
iiii-jjjj is 0000-[0001|1100]
1011 36 1010-0000 0000-0000 0110-0000 0000-0000 1100
1001-0001 0000-0000 0000-0000 0000-0000 1100
1001-0001 0000-0010 0000-0000 0000-0000 1100
1001-0001 0000-0010 0000-0000 0000-0000 0001
1100 40 CD info aaaa-bbbb-bbbb-cccc-cccc-dddd-dddd-eeee-eeee-ffff
where:
aaaa is 0000 for no CD, 0001 for CD in drive
bbbb-bbbb is a BCD encoding of the first track number
cccc-cccc is a BCD encoding of the last track number
dddd-dddd is a BCD encoding of the total playing minutes
eeee-eeee is a BCD encoding of the total playing seconds
ffff seems to be 0000 for no CD, 1111 otherwise
1101 60 0000-0000 0000-0000 0000-0000 0000-0000 0000-0000 0000-0000 0000-0000 0000 (No CD?)
0001-0000 0000-0000 0000-0000 0000-0000 0000-0000 0000-0000 1000-0000 0000 (CD In?)

 

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