pgmfi.org

i like that idea with the switched jumper,

Our P30 project is now complete. I will post more photos shortly.

In the meantime, here's some added info:

We used an ANGO LA6T PRofessional Ultraviolet EPROM Eraser to erase our chips, usually over 15 minutes - this does the trick.

We then used a CHIPLAB Pro from DataI/O Corp using software version 6.10 on a PC using Windows98 to check and verify all EPROMS before burning. We have programmed about 12 chips and will test them in the car once the B16A install is complete.

A custom data cable was made up to hook the P30 to our laptop.

Changes we made ...

1. Converted the Max233 to a female connection (early photos showed a male connection).
2. We made the Max233 board ourselves and hardwired the 4 pin cable for robustness.

Cheers for a safe Christmas

Peter

Here is a photo of the JDM P30 ECU and connecting RS232 cable

Here is the J1 Jumper switch and the RS232 port. Note that we have socketed the Max233 board for easy swap out if required,

I take it you made sure that switch is not in the way of the mounting screw... Looks pretty trick!

Outside of ECU with switch and female RS232 port

Here's the inside of the ECU with the EPROM mounted.

Because its a switch it can be moved and the unit screwed down inside the car.

Toggle moved to left to allow access to lock down tab.

hi i curently chipped p08 ecu as you mentioned the caps are not

necessary ,when i solder j1 jumper ,i got ecu went into limp home mode

any idea will be appreciated

Just to clarify a little, C49 & C50 are decoupling caps. Their purpose is to prevent noise on the Vcc power traces near the 373 and the PROM. I think it's a good idea to have these caps, but opinions vary as to how much risk you run without them.

C91 and the network of C92 plus the resistor next to it are filters there to ensure proper edges with which to latch data using two signals.

One of the signals these components cleans up is /PSEN (active low Program Strobe ENable). Program instructions from the PROM are latched onto the processor on the rising edge of /PSEN.

The other signal is ALE (active high Address Latch Enable). The lower bits of the instruction address are latched into the 373 on the falling edge of ALE.

If there is any ringing on these two signals, or if the edge is not clean enough, the latches may latch at the wrong time, getting the wrong data, or in the worst case they might hang, but that is extremely rare. I am currently running without these caps, but they were probably put in there by the designers for worst case conditions. We'll probably never see the worst case conditions, but we might get caught some day.

Hello guys!
I want to tell you something about capasitors.

I have two JDM P30 ECUs with a factory installed external ROMs. P30-900 AT and P30-950 MT.
Both of them have C49, C50, C91 and C92 installed on the board. C49 and C50 are brown color and marked "A4", C91 and C92 are white color and marked "A1". So, when you add external ROM, this capasitors MUST BE soldered in. Japaneses wouldn't make the places for components without reason.


Does anybody know, where I can read about capacity of A1 and A4? Maybe someone knows its values?



infotechplus.


Where did you find this information? Please answer.

These values were in the WIKI.

Or you could measure the value from one of the capacitors.

Im having a really hard time finding a .00001UF cap, am I miss reading this somehow?

Edit: I found a 1PF cap finally! But I have all kinds of options, like

CAP-CER SM 10PF 50V
CAP-CER DISC 10PF 50V
C-CER MONO 10PF 100V COG

And so on.. What do I need to look for? Will http://www.mouser.com/index.cfm?handler ... deid=58124 work?