Other Parts Discussed in Thread: AM4378
Below are questions about Pin Conflict for AM437x (AM437x General Purpose Evaluation Module (EVM) Schematic )
We need 4 Function to Work together on AM4378. HDMI.PRU Ethernet, MMC0-SD card, MMC1-eMMC or NAND Flash(Alternative).
1.Function 1: HDMI. DSS -> Only One Pin can choose in PinMux Tool for DATA13.->D19, Same chipset SIL9022 as GP EVM board.No Pin Conflict.
2, Function 2: 100M Ethernet -> PRU MII1, Because D19 is used for HDMI, mii1_rxer has to use B3 Pin.No Pin Conflict.
3, Function 3: MMC0 For SD Card. No Pin Conflict.
4, Function 4: MMC1 For eMMC. Pinmux does not assign eMMC_Reset Pin.No Pin Conflict found.
But we check the GP EVM board, eMMC_Reset is controlled by "WPN", and it is in Conflict with MII_RXER, Pls check below (Function 5) for detail.
5.Function 5 Nand Flash: Be note, Function 4 and Function 5 are alternatives.
Nand Flash as EVM design: AM437x General Purpose Evaluation Module (EVM) Schematic
We found "Wpn" is Pin Conflict.
In GP EVM Schematics，wpn is used for Nand Flash Write Protect。
My question is :
Because B3 is used for MII_RXER, Could we move wpn to another GPIO(For example P25, IO Voltage is 3.3V)。
Assuming we have 2 user Cases:
Case1: The system needs to Bootup from GPMC Nand Flash（or MMC1 eMMC）。
Case2: System boot up from MMC0 SDcard only，NAND Flash（or MMC1 eMMC） are used for storage。
In which case we can move "NAND_WPN" to another GPIO?
For the "MMC1_RSTn" or "NAND_WPN" signal which GPIO is suitable?