Dear all,
In my application it works fine in performing single synchronous read from external fpga using GPMC.
But it has an issue in burst synchronous read, especially two word burst read, that GPMC_OEn stretches one more clock than expected.
Does anyone help me understand what happens in my case?
- Processor is am3358
- Synchronous burst read/write @ 50MHz, that is GPMC_CLK is GPMC_FCLK / 2 (GPMCFCLKDIVIDER=1h)
- Non-address multiplexed
- Bus width is 16bit
- CSOnTime = OEOnTime = 0
- CSOffTime = 4 / OEOffTime = 2
- RdCycleTime = 4
- RdAccessTime = 2
- PageBurstAccessTime = 2
The next picture looks ok in single synchronous read by reading 16bit-length data from GPMC region.
Yellow is GPMC_CLK. Red is GPMC_CS0n. Blue is GPMC_OEn.
Next picture is two word synchronous burst read by reading 32bit-length data.
This is not what I expect. GPMC_OEn (blue) is 1 clock longer.
Here is a list of register setting. Could anyone please point out what is wrong within it?
Thanks for reading my post.
M
