I have one of these TCU’s that has the non AISN Marked MCU for the shop to do some research on and attempt a backup. This givesme a clue as to try and figure otu what MCU is used on the plastic sealed TCU’s will take some research and testing but armed with data sheets of the Hitachi Devices form the era may get lucky. I may start that when the snow starts or melts never know. But lets tackle this device first!
The MCU is a Renesas Hitachi H8/3294
I have been Seeking a BPM Microsystems ASM64PQH Adapter or ASM64QA, ASM64QHC, SM64QA, SM64QHC so I can backup this chip with the BPM
Microsystems 1710 Programmer For a long time more then 6 months now. The Adapters new are very Expensive and second hand market has been dry and this firmware backup budget is tight.
From the info in the Data Sheet my other alternative is to make my own adapter and read it as a HN27C101 eprom which I will need to find the time to do it.
Info Form the Data Sheet. These type adapter were common for devices produced in the 90’s.
My Xeltek 6100N, 7500, and a few other support the HN27C101
So we need to build an adapter..
I spent a little time and made a Schematic just using nets to keep it simple.
I also designed a quick adapter circuit board. Since I don’t want to expose this chip to too many thermal cycles, I’ll be making a version with a ZIF socket later on. For now, this board serves as a practical, last-resort option for working with Renesas/Hitachi H8/3279 and H8/3294 64 pin QFP devices.
Gerber files will be posted once I receive and test the first batch.
Boards will be made available after testing for $6.49 each + shipping, and include header the pins. (Click Here to Purchase)
ZIF Adapter Board (Rough Draft)
This is an early draft, I plan to refine the design before sending the prototype for production. I’m still deciding which ZIF socket to use Enplas or Yamachi most options for this package are quite expensive about $100 to the door, so I’m exploring a few alternatives before finalizing the layout.
November 01 2025 I Received the Boards and I made a mistake #1 being the mcu pads need to be a bit longer, I relied on the LCSC / Easyeda Pro foot print I should have measured it. It also seems like mcu is starting when used in the Xeltek it should not be. Reading results in different data in some areas. When using the BPM Microsystems 1710 I get Verify and Compare Good. I do get an error on device ID but that’s common with these type of adapters sometimes ya need to used older tech.
I have tried it on the Xeltek 6000, 6100, 7500, Topmax II, and Multi Apro the same results Random Data on reads like the MCU is Running again it should not be. Cannot get a verify. I get the same data with multiple reads with the BPM 1710. I also tried another BPM Programmer and get the same data. I will also be on the hunt for a BPM ASM64PQH Adapter to verify before I waste any more time on this.
In the Data sheet there is this bit of info.. on Verification. Still dont explain why it will read the same data twice with the BPM but not with many other programmers unless the MCU is bad common onthese TCU’s.
I think this is the issue..
For now I will assume the BPM backup is correct. But I want to be 100% sure before I make it public.
Last Updated on November 2, 2025 by Steven Rhine