Post Go back to editing

Info: Booting from CFI Parallel Flash - ADSP-21262 or ADSP-21364

The ADSP-2126x & ADSP-21364 DSPs have a multiplexed parallel interface that always reads and writes in 32 bit word increments. This can be two consecutive addresses for 16 bit words or four consecutive addresses for byte wide transfers. You cannot turn off packing and unpacking.

This does not present a problem with reading, but it is a showstopper for writing CFI compliant flash. CFI flash requires that addresses be toggled from x555 to 0xAAA (byte operation) between each 8 bit word for write and erase instructions.

The EZ-Kits use a non-CFI flash, the AMD/Spansion AM29LV081B. The address is ignored (don't care) for all commands, which avoids the 32 bit packing issue. Recently, we heard from a customer that the 29LV081B is EOL (end of life). This is going to be an issue if your design uses on-board programming using a Danville dspFlash programmer or an ADI ICE.

I don't know of any workarounds. As I see it, these are your options:

1. Buy enough AM29LV081B parts to cover your needs. If you know of other current non-CFI flash that will work, we are interested and will add  support on the dspFlash Programmer. BTW, I believe our current support list for the dspFlash is wrong with respect to this issue.

2. Preprogram the flash chip before soldering and don't expect to reprogram later.

3. Migrate to SPI flash. We support most serial devices.

4. Migrate to a newer DSP such as the 214xx family.

Please note this is not at all applicable to newer SHARCs or any of the Blackfins. It only affects the devices with multiplexed parallel port.


Al Clark

Parents Reply Children
No Data