Comments on: HML087 coding plug ROM for BMW E30 instrument cluster

By: Farit

Farit — Fri, 27 Feb 2026 07:11:02 +0000

I added a timing diagram that I measured using my actual coder and the latest SI board.

If the SI board sends pulses every 5.583 µs, then the frequency is 180 kHz.

My measured delay is 725 ns. When I used Attiny, delays were 2-3 µs.

By: Aladin

Aladin — Fri, 20 Feb 2026 14:16:58 +0000

Thank you for your reply.
To summarize your answer :
ATtiny85 didn’t work with the latest SI board (works only with early SI board) -> delays issue ?
Ch32v003 works with the 3 latest SI board ?

If this is the case, normally the CH32V003 should work with the early SI board also.

Do you know what is the clock frequency sent by the latest SI board to the CH32 ?

By: Farit

Farit — Thu, 19 Feb 2026 21:01:54 +0000

Yes, I tested it with the 3 latest SI boards that I have.
The ch32v003 is a 48 MHz microcontroller and it’s pretty fast.

When I ran the code using the ATtiny85 with its 8 MHz frequency, I experienced unacceptable delays. It only worked with early SI boards.
Other people may use assembler code to make their versions work.

Though, I can’t guarantee that my code will work with all SI boards.

By: Aladin

Aladin — Thu, 19 Feb 2026 19:39:26 +0000

Hello,

Is this coding plug compatible with all e30 clusters ?
The reading frequency is not the same for all models ? (30 and 5 microseconds pereiod)