i.MX ProcessorsのトピックRe: i.MX93: FlexSPI Sample Clock Source for reading

i.MX93: FlexSPI Sample Clock Source for reading

Niebel-TQ — Mon, 26 Aug 2024 08:32:28 GMT

i.MX93 has only one pin usable for FlexSPI strobe. When using eMMC with HS400 /HS400-ES the same pin is needed as Data Strobe for eMMC. In the reference manual chapter36.8.2.2 Module Control 0 (MCR0) states, that Field RXCLKsrc=10b can be used to use higher SCLK and achieve higher read data rates.

Since this mode is not implemented in BSP: is this mode tested and usable? Looking at other i.MX CPU (i.MX8MP) the value of RXCLKsrc=10b is marked as reserved. If it can be used, are there other configurations that needs to be adjusted?

@florian_arndt + @danny_john

Re: i.MX93: FlexSPI Sample Clock Source for reading

joanxie — Tue, 27 Aug 2024 01:31:37 GMT

As I known, the customer tested this on imx8mp successfully, besides of Setting RXCLKsrc to 10b, also setting SION to 1 on IOMUXC_SW_MUX_CTL_PAD_NAND_DQS, maybe you can try it on imx93

Re: i.MX93: FlexSPI Sample Clock Source for reading

Niebel-TQ — Tue, 27 Aug 2024 10:14:51 GMT

The DQS Signal for FlexSPI is only muxable at the very same pin that is already used for EMMC Strobe. This is the reason why asking for MCR0[RXCLKSRC] = 10b (SCK output and loopback from SCK pad).

This means setting this mode _and_SION for SW_MUX_CTL_PAD_SD3_CLK muxed as FLEXSPI1_A_SCLK, rigth?

Re: i.MX93: FlexSPI Sample Clock Source for reading

Niebel-TQ — Tue, 27 Aug 2024 16:58:20 GMT

Just a follow up question. The mode 10b (SCLK output clock and looped back from SCLK pad) is not mentioned in the data sheet. What is the SCLK rate that is achievable in this mode?

Re: i.MX93: FlexSPI Sample Clock Source for reading

joanxie — Thu, 05 Sep 2024 07:07:47 GMT

I confirmed that imx93 doesn't have this issue, you can try to use this bit directly, for the clock, pls refer to the data sheet as below

joanxie_0-1725520037439.png

Re: i.MX93: FlexSPI Sample Clock Source for reading

Niebel-TQ — Fri, 27 Sep 2024 15:56:25 GMT

We managed to modify FlexSPI driver (currently on linux 6.1) to accept different MCR0[RXCLKSRC]. First Tests with SPI 1-4-4 @114MHz looking good.

Re: i.MX93: FlexSPI Sample Clock Source for reading

joanxie — Sun, 29 Sep 2024 03:52:17 GMT

glad to hear this, I will close this tread if you don't have further issue about this