Content originally posted in LPCWare by pierre on Thu Sep 18 01:06:22 MST 2014
OK, so if I understand this well :
The ROM bootloader asks the flash chip if it supports quad mode, but does not check if the quad pins are actually connected.
Then it boots in quad mode, and if the pins are not connected, it crashes.
So, I either need
- a new revision which actually checks if the pins are connected,
- or a SPI flash that does not support quad mode, so the bootloader does not activate it
- or an external 3-state buffer for the 2 conflicting pins, which allows the signals I want to pass through when the flash's CS is high, plus reconfiguring the pins properly in soft (not so difficult to implement, I guess I will choose this solution).
Is this correct ?