SARD demo boards, not enough RAM

[KRichard]

Hello!

We have been using SARD demo boards to do some experimenting with MAC 802.15.4, but we are likely to run out of available RAM (4 kB) in the future. We are looking for a way as to how we could interface an external RAM module to the GT60 uC on a redesigned SARD board.

The RF transreceiver uses up the SPI port, what options do we have?

I would appreciate your feedback, thanks in advance!

Richard, Technical University of Budapest (BME)

[bigmac]

Hello Richard,

Firstlly you may wish to consider whether the SPI interface can be shared between the transceiver and another (serial memory) device.  In principle this is quite feasible, but it really depends on timing constrains imposed by the transceiver for the transfer of its received data.  SPI will provide the fastest serial data transfer.

Another possibility is to use a IIC serial memory device, however data transfer will be significantly slower.

For the serial memory, you might consider Ramtron FRAM devices, available with either SPI or IIC interface.  The FRAM memory provides non-volatile storage like EEPROM, but allows fast writing of data, and does not have the write endurance limitations of EEPROM or flash.

There is also a serial RAM device from NanoAmp Solutions, but I am uncertain of availability, and the data I have is for a SPI version only.

Regards,

Mac

[KRichard]

Thank you very much bigmac, your answer was a great help. We are going to order some samples from Ramtron.

Richard

[KRichard]

We have tried to order some samples, but Ramtron's website gave back a weird error message and email to their support addresses bounce back (weird error again).

We are considering purchasing M5213EVB coldfire boards to use as FFD devices, but the Ramtron way would have been of course, much cheaper.

Richard