Hi Sankar,
I have feedback from the factory team, confirming that 256MB CS size is working for 16-bit AD mux mode. Here is the description:
"AM335x GPMC 16bit Multiplexed NOR Flash 256MB access should be working now since I have confirmed the GPMC_A27 pin(GPMC_A11 Mux mode 4) functionality for the 128MB+ access.
The GPMC_A27 pin is going to a weird state when configured for the Mux mode (based on the SYSBOOT[11:10] setting) by the Boot ROM at power on reset. Hence configuring again to the Mux mode the GPMC_A27 is not getting asserted. This needs a workaround of setting the GPMC_CONFIG1_0 = 0x0 and then configuring for the Mux mode GPMC_CONFIG1_0 = 0x00001200. After this sequence the GPMC_A27 assertion is happening as expected for the 128MB+ location.
I have verified this on a AM335x ICE EVM v2.1A and accessing through the CCS Memory window.
GPMC_CONFIG1_0 = 0x00001200 – 16bit Multiplexed mode
GPMC_CONFIG7_0 = 0x00000050 – Base Address 0x10000000, 256MB CS# size
Memory location tested for the GPMC_A27 function: 0x18000000
Please try this on your side and provide your feedback."
