Hitachi HD404222 CMOS 4-bit Single-Chip Microcomputers

[Stari1]

Dear Forum Members,

I am looking for a solution in the topic below.

I would like to read program from a HD404222 CMOS 4-bit Single-Chip Microcomputers and write to a new empty HD404222.
I have already checked the datasheet of the IC (uploaded) and created a socket adapter to the reading/programming(writing).
Furthermore, I bought an Prom writer to the project.
XGecu T48 [TL8663G]
The datasheet contains description to the programing (programing like a 27C256 eprom), but the socket adapter built by me not suitable for reading and writing in the practice. The programmer does not indicate an error, but it cannot read the correct values (it reads 1F from all memory address).
I tried to contact Hitachi Japan and then Hitachi USA, but I got no answer.
It would be nice to know if there is an original Hitachi socket adapter for the HD404222 or the exact resistance and diode values for the legs O5, O6, O7, A13, A14.
(Theoretical socket adapter circuit diagram for HD4074224 uploaded.)
Thanks in advance and Best Regards!

 

[std_match]

The resistor values and diodes should have no effect on the data you are reading. Something else is wrong.
Please show the complete schematic for the adapter.
Have you connected all signals for PROM mode according to page 499 in the data sheet?

 

[Stari1]

Thank you very much your reply.
Unfortunately, I have no schematic diagram for this.
I just followed the instructions and connected the IC pins.
The programmer perceives it as if it were a 27C256.
But that seems to be not enough.
Therefore, a factory adapter or its schematic diagram would be good.
Thanks a lot!

 

[std_match]

You have a HD404222, which has a 2k-word mask ROM. It probably can't be read.
The one that can be programmed/read like at 27256 is the HD4074224, which has a 4k-word PROM.
How can you have a "new empty HD404222"? It can't be programmed, the program is in a mask ROM.

 

[danadakk]

Is processor read protected so no one can hack its code ?


Regards, Dana.

 

[Stari1]

You have a HD404222, which has a 2k-word mask ROM. It probably can't be read.
The one that can be programmed/read like at 27256 is the HD4074224, which has a 4k-word PROM.
How can you have a "new empty HD404222"? It can't be programmed, the program is in a mask ROM.

Thank you very much!
Are you sure?
This is not a very good news.
It is possible the buy HD404222 from more sellers.
The IC-s operation is not the totally same.
Old Denon HiFi amplifiers (PMA series) use this IC.
For example: DENON PMA-495R
In the event of a lightning strike, the microcontroller is damaged and, for example, cannot be repaired in this case.