User programmable 4bit micro? Just for fun

[ddavidebor]

Hi guys.

Do you know if there is any user programmable (assembly obviusly) 4bit microcontroller?

Not microprocessor, microcontroller.

[free_electron]

toshiba hitachi oki mak plenty of thoae. most commonly found in older car radios.they are microcontrollers but are typically mask rom. there are bond out version where you can put an eprom on their back to run code.

[brainwash]

I think also Holtek might still make them, for toys mostly, but it will probably be an exercise in reverse-engineering since AFAIK they don't provide all the details except under NDA and with >1k purchases. This is just what I heard, don't quote me.

[amyk]

Atmel used to make them, look at the T48C series.

There's the EM6580 which is Flash: http://www.emmicroelectronic.com/products.asp?IdProduct=215

An odd cut-down 8051 derivative (a 4051?) : http://www.coreriver.com/product-lines/CORERIVERmcu_linkATOM11.html

The majority of 4-bit micros seem to come from the far East: Epson, Hitachi, NEC (now Renesas), Samsung, Sony, etc. not to mention the countless Chinese manufacturers...

I don't think Holtek still make them, or if they do they don't say so on their site.

[Stonent]

I took apart a remote for a Dell TV once, it had a 4 bit Renesas Micro with integrated keypad controller.

[westfw]

I have some Toshiba TMP47P443VN chips.  They're an apparently rare one-time-programmable chip; they program like EPROMs (parallel interface, odd voltages, funky algorithms.)  I don't know if there ever were any flash, eeprom, or eraseable EPROM 4-bit microcontrollers; as others have said, they were mostly done in mask-programmer versions.  There are very limited tools (assemblers from Nth parties, etc), and the instruction set architecture is sort of a cross between a stripped 8080 and the less pleasant 8-bit PIC chips: one AC, one pointer register, a bunch of instructions that operate directly on data memory.

The datasheet says:
4k * 8 instruction memory
256*4 data memory.
1 us instruction time at 8MHz.
4.2MHz at 2.2V
92 instructions, incuding table lookup and 5bit to 8bit conversion instructions
15 level subroutine nesting.
6 interrupt sources.
23 pins of IO
Interval Timer
two 12bit timer/counters
"Serial" interface
8bit A-D with 8inputs and 24us conversion time
Pulse output (buzzer drive or Remocon carrier.)
Zero-Cross detector

I haven't managed to do anything with them yet.  I'm not sure I ever will; I'd forgotten how unpleasant things were in the pre-flash-memory days.

[AlfBaz]

I'd forgotten how unpleasant things were in the pre-flash-memory days.

I still remember how excited I got when I received my first UV erasable micro!

[AlfBaz]

Just for fun

You may be able to double or even triple your "fun" and learn something useful in the process.
Get an FPGA/CPLD dev board, create your own 4bit micro and program it

[brainwash]

http://www.renesas.com/products/mpumcu/720/index.jsp

http://datasheets.chipdb.org/National/COP400/NS_COP400_Family.pdf

http://en.wikipedia.org/wiki/TLCS-47 and http://en.wikipedia.org/wiki/4-bit

https://www.nuvoton.com/NuvotonMOSS/Community/ProductInfo.aspx?tp_GUID=8416b88a-0bd8-4173-8ecb-cc30a4a69caa
https://www.nuvoton.com/NuvotonMOSS/Community/ProductInfo.aspx?tp_GUID=2e197b1c-9cdb-4a07-9c3f-27f476247915
https://www.nuvoton.com/NuvotonMOSS/Community/ProductInfo.aspx?tp_GUID=11734267-2901-4370-a569-cb8642e92fea

Seiko and ST (part of STC series) also have some with LCD controllers.

There's a wealth of 4-bit chips in toys, remote controls, recording machines, [old] house/car alarm systems, watches, simple handheld games, weather stations. I suspect Chinese distributors are the go-to suppliers for these but I doubt any documentation is in [understandable] English. Like with those all-in-one ARM dev boards. Toolchains are also hard to get by, you'd spend less time writing directly in machine code than finding one.

I second the approach of FPGA and/or software simulation. I also don't see the point very much unless writing FW for a 5M+ market where 1c/part cost makes a noticeable difference.

For an easy ride just go with this: http://e4004.szyc.org/

[ddavidebor]

Thank you, interesting!