WTD: ARM uC with low pin count

The two are mutually exclusive. 16 pins data bus plus 24-32 pins address bus, plus power and ground - don't you want any I/O?

I/O is not an issue for me.

Just like the old days, I would like a processor. Not the entire system on a chip.

Thanks

Donald

I doubt you're going to find this under 100 pins. If that's acceptable then try AT91R40008, which is in LQFP100.

I don't think anyone sells what you want, which is essentially a bare ARM core with bus interface on the side. Vendors make their money by value-adding. ARM devices aren't used in general-purpose computing, they're intended for embedded devices.

If I can send in my wish list, I want one with:

16 data bits + 16 address bits (row/col multiplexed) + 8 usb (host + device) + 4 jtag + 8 I/O.

I want it in 84 PLCC. Anyway, if you really want it, we can always pack the die for you. But it's going to cost quite a bit.

Low pin count is sort of a relative thing. I found that the AT94R40807 with 100 pins had enough pins for address, data, chip selects and a reasonable amount of I/O. Certainly 100 > 64 > 48, etc.etc. But a 100-pin qfp is certainly easier to work with than a BGA chip.

For me, the dividing line runs not between pin counts, but between packages that I can solder by hand (QFP) and those that require special equipment and layout techniques (BGA).

Mark Borgerson

If commercial IC's are not available, I wonder if the IP is available for a cpld or fpga core then you could choose any i/o configuration..?.. not exactly in the arm spirit.. but could be a solution..

He can still get a z180 in a 64 pin package. It has various ports and timers built in, and uses external memory.

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Would that be a zARM then ? ;-)

You can get ARM7 soft core in Actel FPGA.

It doesn't give you the source code, their FPGA tool insert the core code for you. But you don't have to spend money on the IP license.

regards Joe

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Not really a serious suggestion, but 1987-vintage ARM2 came in a PLCC84. 8 MHz too, so no worries about PCB speeds :-) The main limitation is only a 26 bit address bus and no onboard MMU (that was farmed out to the DRAM controller chip). Some of the assembly is very slightly different ('26 bit mode' means status flags were stored in high bits of the PC instead of a separate status register) and some recent instruction additions aren't supported but gcc will generate code for it. The bus is fairly friendly (a bit like ISA).

Datasheet here:

I have a spare one I can send you if you like :-)

Theo

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Theo Markettos                 theo@markettos.org.uk
Clare Hall, Cambridge          atm26@cam.ac.uk
CB3 9AL, UK                    http://www.markettos.org.uk/

This looks to be close: ADUC7027

but its not available yet.