I have a custom board, that has both MMC0 and NAND as boot devices. SYSBOOT[0:4] has following configuration: 00100, i.e. UART0->XIP->MMC0->NAND and non-multiplexed access.
NAND has 8-bit, but according to TRM ROM boot uses 16-bit address access. GPMC_AD0-AD7 go to NAND chip, but AD8-15 are connected to other components. Some of these components are inputs for am335x. So in this case I have a signal conflict: output vs output for a short period of time, till I can change the pinmux from U-Boot/Kernel.
Another signal conflict occurs on A0-A11 pins, as they are connected to a network PHY via RGMII2 interface. In this case two outputs work against each other during XIP detection phase.
Can it possibly damage the am335x?
Regards,
Yegor