Tiny dual port RAM needed

A $1.00 CPLD from Xilinx or Altera would do the job. You would just have to code up a little VHDL or Verilog to define the dual port ram function.

Eric

I predict he'll need a macrocell per bit and it will cost him more like $3 per part.

It will still be the best solution though.

Code it into a PLD/FPGA, Altera and Xilinx have standard logic cells for dual port RAM, just get one with enough D types or memory bits.

All depends on how fast an access speed and size of package is actually 'small' that you need. Let alone 5V or 3V3, power budget and cost.

If you can find an equivalent part for the National 74F410, you could use smaller PLD to do the dual porting of two devices giving you 16 x 8 RAM/register file from two 16 x 4 devices.

There seem to be several suppliers of the 4 x 4 register file 74HC670 series. This would need four devices.

Buying small size memory for LUTs and similar is getting more difficult.

If the data is loaded once (or infrequently) but read from both sides, you could pipeline the data into a Logic Devices L29C525 and hold the data for reading.

As we don't what you are trying to dual port an what for these are only outline suggestions I would give at this stage.

That is a hole in the market.

There are smaller sized Dualports, but they tend to be old, and priced like 2716 EPROMS :) Dallas used to have a 4 port serial memory, and they still have a 2404 serial Dual port, and DS1609 is parallel dual port, but that is tagged not for new designs, tho you can still buy them...

Alternatives would be CPLD, but that would use many macrocells, small FPGA, or maybe you could adapt to use a couple of HCMOS FIFOs - those are still active devices ?

-jg

Take a look at the various cmos clocks. Many of these have some ram included.

Hul

Davor.S wrote:

"Davor.S" skrev i meddelandet news:d7nnn6$b72$ snipped-for-privacy@sunce.iskon.hr...

The soon to be available AT94K05AX will give you six 32 x 8 DPRAM, and an AVR microcontroller in 8 x 8 mm. There is already silicon on the AT94K10AX which gives you more and is more expensive.

Bad suggestion below, sorry. I missed "dual port".

Hul

Hul Tytus wrote:

If your can tolerate slow access times you can program a small micro.

Depends on how you define slow - I'd guess a Ubicom (formerly Scenix) SX chip running at 75MHz could probably do the job at system speeds of up to about 10MHz

Another option (if they are still in the catalog): Motorola MC68HC34. We used to use them by the hundreds of thousands as dual port rams. Worked quite well.