Boot Option for QSPI Flash for RT105x

[deega_jung]

Hi,

At RT105x,

Could you let me know, what is a different boot option on BOOT_CFG[2:0] by "000b" and "111b"?

Customer use case is a below,

- QSPI Flash interface : GPIO_SD_B1_06 to B1_11.

- LCD Control with SPI or I2C : GPIO_SD_B1_02 to B1_05.

According to EV-KIT circuit, it's recommend the FlesSPI_DQS(GPIO_SD_B1_05) pin floating when using the QSPI. Can't we use this pin for something else?

And can "GPIO_SD_B1_02 to B1_05" pins be used for other function like LCD control?

Thanks,

Deega

[jingpan · Accepted solution]

Hi @deega_jung ,

1. I think you mean the BOOT_CFG2[2:0]. When it is 000, it use default  FlexSPI port, that is GPIO_SD_B1_06 to B1_11, just like the EVK. When it is 111, it use FlexSPI NOR 2nd option. Please refer to table 9-1 in page 196.

2. No, you can't use GPIO_SD_B1_05 if you want QSPI faster than 60M.

3. GPIO_SD_B1_05 is used by BOOT. It can't change during boot. But FLEXSPI_A_DQS has a backup pin GPIO_AD_B1_09. If it must use GPIO_SD_B1_05 for LCD. Maybe you can let FlexSPI work in a slow speed when startup. Then mux DQS to GPIO_AD_B1_09 and then let Flexspi work at high speed.

Regards,

Jing

[deega_jung]

Hi Jing,

Thank you for your comment, I've further question with the below,

If we use QSPI Flash and do the rest of the pins differently, is BOOT_CFG2[2:0] "111b" more suitable than "000b"?

And is BOOT_CFG2 [2:0] "000" an option for the OCTAL-SPI Flash?

Thanks,

Deega

[jingpan]

Hi,

I don't understand what is "do the rest of the pins differently". BOOT_CFG2[2:0] is select by the pin by default. Please look at table 9-4 in RM.

BOOT_CFG2[2:0] 000 is not for Octal flash. Please check table9-9.

Regards,

Jing