NEC UPD54304B

[doccybrown]

I've got this baby but cannot find out what it is,
any hint would be very appreciated!

[UMMR]

Hello,
I have in my collection a NEC D7809 microcontroller in a similar package.
Paolo

[gshv]

I looked at my NEC databooks, and I haven't found anything close to it. Almost all of my my databooks are for microprocessors and microcomputer products, so these could be something else, perhaps memory.

Gennadiy

[Neon_WA]

I would be looking at some early datasheets of the UPD754304
ideally pre 75XL or 75X series naming which I think first came about in 1994

[doccybrown]

Thanks for your help guys!
Yes I think there are good chances it is the direct predecessor
of the 754304, a 4bit microprocessor with 4kbit of integrated mask
ROM. After all the five digit p/n is still very strange.
Most processors made by NEC have three, four or six digits in the p/n.
Likely the generation between four and six digits was very short-
lived or just made for special applications like calculators.
NEC had some specialized UPD751-derivates with VF-display
outputs which could be used for calculators, clocks or any other
kind of displaying computed informations.
These are UPD553C, 545C and D547C and D554C for example,
all have integrated mask ROM and bit of RAM so typical MCUs,
next step in naming these devices was perhaps UPD543 and
adding 04 at the end for 4kbit of mask ROM.

[Neon_WA]

here's one for you Doccy to work out D57107B

[doccybrown]

Alas I could not yet figure out what both chips are but still think they have a uPD751-core as base for any kind of controllers.