NVRAM Board For The VS Ecotec and Later PCMs

[VL400]

Well the next phase in development is here, getting a DIY tunable solution on the VS Ecotec and newer PCMs. My current NVRAM board is not suitable as the newer PCMs use a different method of limp home and as such only have a 36 (or 37) pin memcal connector as opposed to a 66 (or 65) pin connector on the older style ECM/PCMs

For this NVRAM board the same DS1245Y NVRAM IC will be used but it wont have the dual map feature anymore as we need to use the entire 128k of memory.

The only hangup was finding the R/W signal from the main processor. This line is very important on the NVRAM board as it tells the IC if it needs to read or write which is the whole reason behind having the NVRAM in place of the EPROM - which like its name sugests, is Read-Only Memory.

mc68hc11f1.jpg (60.94 KiB) Viewed 6787 times

In the early applications the R/W did not appear on the memcal connector at all so a jumper needed to be added to the underside of the PCB. After a few hours searching by holden202 and antus, holden202 discovered the line actually appeared on the memcal header as an unused pin of the VS PCM. So this meant that the NVRAM will be a plug in conversion, no soldering required, and a regular ALDL cable to the factory interface port under the steering column to communicate.

VS_PCM_RW_Pin.jpg (61.97 KiB) Viewed 6787 times

A shematic has been drawn and the PCBs will be in production soon enough....

PCM_NVRAM_Schematic.jpg (54.56 KiB) Viewed 6787 times

[Holden202T]

its nice that holden finally got their layout suited to our needs

the next generation in tuning!!!

[antus]

Cant wait for this. Looking forward to hacking away on some currently reasonably undocumented hardware

[jacomms]

Hi guys

this is where im up to with the VS/VT also.....then just last week an upgrade to a VX V6 Auto. 445 PCM DMTY. I havent dumped the flash chip as yet (AM29F010B) I made myself a NVSRAM memcal for the VT not even thinking that VX was the ECU change (been a while since I worked for Holden) ......so upon pulling apart the 445 and finding a 32 pin PLCC chip the mind got to ticking.....this is still only a 8 bit device as is a CY14B101L (and many other NVSRAM) ....its a 32 pin device also but is a SOIC...... I was thinking of doing a PCB run to adapt this for real time.....that is unless someone has already started a design or is using a nother method?? I havent checked to see if all the hedderpoints (which have no headder) on the 445 ECU go back to the flash as yet .....hahaha needed the car ...doh!!! and also havent checked ecu pinout to see if i can do a ECU swap with a slight connector mod (cant be shy now can we). any thoughts???

[VL400]

Welcome aboard jacomms, since the above post there is now a NVRAM board for VS and VT and have started looking at the VX/VY flash PCMs also. There is some info in here about the flash based PCMs

The header pins have all thats needed to run a memory chip there, just need to remove the current flash memory. There are a few options, 1) can reflash the current AM29F010 chip, but it would be like the old LS1 way of tuning (drive and log, make the changes, flash the calibration) or 2) remove the 29F010 and add a NVRAM to the header pins. Disassembling the bin so realtime code can be added is the hard part!

[Dec_head]

I decided to try fitting the nvram in my sc vt got it all up and running but i can't find a chip marked mc68hc11f1 on either a vs or the vt sc ecm i am assuming i need to run a wire from that to the pin on the header for writing any chance someone could take a pic

[antus]

nah you dont, we found it was built in to the pcm from the factory on pin36, so no mod is required, its already connected up to the header. The CPU is delco branded, and carries no motorola markings, but we figured out what the equivalent moto part is.

[Dec_head]

cool thanks time to go play this car is on the rd might be a better learning curve for me.

[Dec_head]

I connected a 10k resistor is that right not sure what you meant by semi i thoughtt that wa a variable anyway it worked fine then do i connect the the ecm pin 36 to the nvram rw pin side of the resistor ?

[VL400]

A 10k resistor is fine and yeah pin 36 goes to the r/w pin of the NVRAM.