Boot from non-quad SPI flash

[lpcware]

Content originally posted in LPCWare by pierre on Wed Sep 17 02:22:21 MST 2014
Hello !

I need some extra I2S pins on LPC4330, so I'd like to use the SPIFI flash in simple SPI mode (not quad mode).

I made a simple test : unsoldering the flash SIO2 and SIO3 pins on my LPC4330 Xplorer board, and using pullups to the flash's VCC.

It did not boot. So, I resoldered them and it works again.

Is this supported ? I don't care if flash access is a little slower as all my code runs from RAM.

[lpcware]

Content originally posted in LPCWare by pierre on Sat Sep 20 06:11:21 MST 2014
That's a simple fix. Thanks !

[lpcware]

Content originally posted in LPCWare by mc on Fri Sep 19 06:04:43 MST 2014
Hi Pacman/Pierre,
Yes, if device is recognized by the bootrom as an SPI device( Not QSPI) LPC18xx/LPC43xx will boot in SPI mode.

As Pierre is not using QSPI feature of the flash device, it will be good to use device which just supports SPI.

[lpcware]

Content originally posted in LPCWare by Pacman on Thu Sep 18 21:24:28 MST 2014
Uhm... Doesn't the LPC43xx have the option to boot in SPI mode from a normal SPI device ?
-Eg. if you replace the SPIFI device by a SPI device, I believe it would have a chance of working without adding extra hardware.

[lpcware]

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 ?

[lpcware]

Content originally posted in LPCWare by mc on Wed Sep 17 08:29:34 MST 2014
Hi Pierre,
Boot loader will boot in quad mode, if xSPI device supports it. The solution could be to boot in quad mode and then during initialization of your code put device in SPI mode.
In future revisions we will have both options.