VY/VZ Headunit Mod for Aux Input

[TazzI]

If I could get my hands on the Commands XLS and the lcd interface picture they would be very beneficial.

I know I saved them on the lappy somewhere for a rainy day. Will see if I cant filter them. I remember doing a bit of research before that adding an iphone connection to the arduino wasnt much harder to do, only difference is adding in the phones comms line in if we want to grab current track playing ect. And adding a appropriate voltage for charging if wanted. Might be on the "try out later" once a working unit is made.

But I have.. 6 or 7 units here at home at the moment.. so trial and error is too much of a hassle here

[atreidae]

Well. my little Arduinoscope isn't up to snuff and I don't have a logic analyzer. looks likes it time to order a buspirate.

I've downloaded the Datasheet for the Micro in the LCD panel on to find the SPI pins could be one of a about 30 pins and their configured in software so that doesn't help me at all.

So far I've managed to find SS and I think I've found MISO and MOSI but have no idea which is which and I cant find the CLK.

(Yes, I'm very new to bus hacking

[atreidae]

Progress..

NOTE: Turns out this is an MSBFirst SPI bus and not an LSBFirst SPI bus. all these packet captures were taken assuming LSBFirst (default on my app)

I'll update this after I recapture it all.

After turning one of my Arduino boards into a Logic analyser (with a whopping 1k of memory I get 2ms at 200mhz! Time to buy a Bus Pirate) I've managed to find the interesting data and I'm starting to decode the SPI bus.

When pressing a button
LCD pulls CS low.
Motherboard responds with 0x80 (RTS?)
LCD Transmits 0x50 (ACK) followed by a two byte key code (checksum maybe)
Motherboard responds 0x50 (ACK?)

At the moment (due to my noobishness) im assuming Mode 1 and LSB first. hence all my measurements assume this

Pins for those playing at home.
I'm probing the 14 pin connector attaching the LCD to the board

Pin 1 is closest to the center of the PCB
#WARNING THERE IS 12V+ IN THIS CONNECTOR

Pin 1, Unknown, reads Low
Pin 2, Unknown, reads Low
Pin 3, +12V. Only present when LCD connected (backlight maybe?)
Pin 4, 5V rail for Micro on LCD board
Pin 5, SPI Bus, MOSI (i think)
Pin 6, SPI Bus, MISO (i think)
Pin 7, SPI Bus, SCLK
Pin 8, SPI Bus. Chip/Slave Select
Pin 9, Unknown, Reads low
Pin 10, Unknown, reads low
Pin 11, Reads low. occasionally spikes. havent looked into
Pin 12, normally High
Pin 13, blank
Pin 14, Looks like another +5 rail

(edit, dumping some more of my notes, just incase I evaporate)

Key First Byte Second Byte
CD 0xd8 0x64
Pause 0x68 0x84
FM 0x4 0xD4
AM 0x84 0x34
ASM 0x44 0xB4
LOC 0xC4 0x74
Time 0x98 0x24
EQ 0x78 0x94

Eject 0xF0 0x58
On 0xA0 0x8
Off 0x50 0xA8
Seek < 0x80 0x30
Seek > 0x60 0x88
Tune < 0xFF 0x50
Tune > 0XD0 0x68
FR 0xA8 0x4
FF 0x58 0xA4
Track Scan 0x38 0xE4
Track Repeat 0xE8 0x44
Track Random 0x48 0xB8
1 0xB8 0x14
2 0xFF 0x50
3 0xC8 0x78
4 0x70 0x98
5 0x90 0x28
6 0x20 0xF0
Rotary encoder in 0xF8 0x54

Optical encoder uses a different format

Right
MOSI 55,00,00,00,00,10
MISO 00,80,10,80,50,00


Left
MOSI 55,00,00,00,00,90
MISO 00,80,90,80,D0,00

[atreidae]

So I think i might be running into the limits of my knowledge here.

First off. it appears the bus is MSB not LSB. so I need to capture button presses again.
Secondly when I plug my arduino's SPI interface into the bus it introduces enough noise (the pullups I guess) to halt communication between the Motherboard and the LCD. at which point it shuts down.

I'm looking at Bit banging with the non hardware interface on the arduino so I can get some tweakability on the pins. (ie slave mode)

Any thoughts from experts here would be great.. How do i hijack an SPI bus and not upset everything on it.


Edit

Okay, Looks like I'll have to use a software SPI implementation (the on board Micro's appear to be using software anyway) as the arduino outputs are always driven, ie not floating.

a thing thats just thrown a massive spanner in the works however is that pin 12 seems to be be SS.. I have no idea what Pin 8 is doing now I understand the SPI bus better

Those old attachments would come really in handy now.

[TazzI]

Ah looks like youve been very busy!

I havent been too successfull on recovering the images. Although will check the backs for them. I know I saved it all into a word doco.. back cant figure the name out to same myself!

[TazzI]

Headunits out, wired up for testing, arduinos set and bus pirate ordered and on the way. 100% committed to this. Last thing now is those wiring diagrams. Will see if Nem isnt lurking around.

[TazzI]

Pics are back up

[atreidae]

I didnt get a chance to spend any time on it this week.
Trying to get a bunch of PC's out of the garage.

Hoping to order my buspirate this or next week

[TazzI]

No worries, mines on the way so should be able to get it all hooked up with the ic hooks and tinker.

[TazzI]

Bus pirate has arrived! Time to start probing!. Ill attempt to use the pinouts as provided from Nem, hopefully we can test out some of the messages and see how it goes.