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16-bit Multiplexed NOR Flash Issues

JayWhy
Intellectual 340 points
Other Parts Discussed in Thread: AM3359

Hi all,

I'm having trouble getting my Starterware-based project to write/read from NOR flash. I am using a PC28F00AP33-TFA for my NOR flash. I am interfacing to the AM3359 on a custom made board. I have configured the GPMC module for 16-bit, AD multiplexed NOR device. I am able to read the Manufacturer Code and Device ID Code. 

My issue is that when I write to a 16-bit location on the device, it appears that the write also occurs at the next memory location. I experience this issue using asynchronous single read/writes. 

I may have incorrect timing settings, but I am not sure where to look. Does anyone have any advice?

Thank you in advance for any advice you may have. 

  • 0
    Intellectual 340 points

    We discovered that this was a schematic issue.

    Looking at Table 7-5 in the TRM, it indicates that gpmc_a[0] is not used when configured for 16-bit multiplexed device.

    Additionally, GPMC_AD[15-0] should ALL be connected to the Flash device's address lines. 

  • 0 in reply to JayWhy
    Intellectual 340 points

    After board rework, I found the following issue and solution:

    The TRM / Datasheet for the AM3359 has a bit of a conflict. If you want to connect to a Multiplexed Address/Data 16-bit device, you'll need to use the GPMC signals GPMC[11:1].

    The IO configuration for these signals say that a mux value of 0 will make them behave as GPMC_A[11:1]. A mux value of 4 will force them to GPMC_A[27:17]. 

    To use the GPMC peripheral for a AD Mux device, the IO mux for GPMC_A[11:1] must be set as value 0. 

    I have verified these settings on real hardware.