P1024 GPCM mode

[arunp]

Hi,

I am using P1024 in my design. In that I have connected 16 bit NOR flash (for booting on CS0#) and an 8 bit Non Volatile memory on the local bus (LPC). Both memory  are working in the GPCM mode of the LPC bus. The NOR flash is configured for the 16 bit GPCM mode and NV Memory is configured in the 8bit GPCM mode. For NOR Flash I am using a demultiplexer  (latch) since flash memory uses the address signals from LA30 (since it is in 16 bit configuration) to LAD8 for address selection and LAD15- LAD0 for data. But for NV Memory the address used are from LA31 (since it is in 8 bit configuration) to LAD12 and LAD0-LAD7 for data, so should I use the multiplexer here also to demultiplex the address and data, there is no common signals in the address and data phase. In 8 bit mode, during the data phase (after the ALE is toggled) will  the signals LA31 to LAD8 be there intact without changing the state? The NV memory require the address signals in the same state for entire duration of the read or write cycle.

Kindly clarify.

Thanks,

Arun

[alexander_yakov]

If my understanding of your question is correct, your question is if upper (unused) part of LAD bus will act as non-multiplexed address bus without need of external address latch. Unfortunately, no.

But you do not need two different address latches, if you already have address latch for NOR flash, you can use output from this address latch to drive addresses of your NV memory. Address latch is managed by LALE signal, this signal is asserted for every address cycle, so the latch will work for both NOR flash and NV flash address phases.

Have a great day,
Alexander
TIC

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[arunp]

Is this applicable for GPCM 8 bit mode also (NV memory is in GPCM 8 bit configuration as the device has only 8 bit data lines), as the LAD15 - LAD8 will not be part of the data phase any way. For 16 bit GPCM configuration (NOR Flash  device has 16 data line) the latch is a must one. Hope these all are valid for P1015 also as it just a single core version of P1024.

Good Day.

Thanks,

Arun

[alexander_yakov]

Yes, this is applicable for both 8-bit and 16-bit modes. Yes, this is applicable for P1015.

[arunp]

Thanks a lot.I am following single demux device for Flash and NV memory, as per your suggestion.