topic Re: LPC553x RM - I3C doc error in LPC Microcontrollers

LPC553x RM - I3C doc error

martingcavallo — Thu, 22 Dec 2022 18:53:49 GMT

Hi everyone!

As I said in another ticket I have been working on the development of an I3C driver. My last task was to define a method to set I3C frequencies. It was really hard, but I understand that I also found some errors in the documentation.

Mainly, I followed the description that is presented in Table 336 Configuration parameters used to initialize the I3C module (on page 1613). Below are the errors that I found:

OBAUD:
- Empirically, I got a result where ODBAUD half-clock time period = (ODBAUD + 1) * PPBAUD high period instead of ODBAUD * PPBAUD high period.
- In the same way, SCL(in MHz) = FCLK / ((2+2*PPBAUD)*(ODBAUD + 1)) instead of
- SCL(in MHz) = FCLK / ((2+2*PPBAUD)*ODBAUD)

I2BAUD: I really didn't understand how the I2C buadrate is set. Following the example on page 1614, I understood that if I2CBAID is:
- An odd number then I2C Ton (high state) = (I2CBAUD -1)* ODBAUD period and Toff (low state) = I2CBAUD * ODBAUD period.
- An even number then 2C Ton (high state) = Toff (low state) = I2CBAUD * ODBAUD period.

However, the empirical results that I reached show that there isn't a linear relation between I2CBAUD and ODBAUD period. The attached image shows what I got. I'm wrong or I'm missing something????.

Hope to hear from you soon.!!!

Regards,

Martin

Re: LPC553x RM - I3C doc error

xiangjun_rong — Tue, 03 Jan 2023 06:43:44 GMT

Hi,

Pls download the latest RM of LPC553x from the link, the latest reversion of RM of LPC553x is reversion 2.0 till Jan 2023

https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mcus/lpc5500-arm-cortex-m33/lpc553x-s3x-advanced-analog-armcortex-m33-based-mcu-family:LPC553x

I suppose that you use the old revision of RM, the table of "Configuration parameters used to initialize the I3C module" is Table 353 instead of Table 336. BTW, the table has updated.

Hope it can help you

XiangJun Rong

Re: LPC553x RM - I3C doc error

martingcavallo — Thu, 05 Jan 2023 17:33:13 GMT

Hi Xiangjun_rong,

Ok, thank you for your response.

I downloaded the new RM and I saw that I3C peripheral documentation was updated. I'm closing this ticket now and open a new one if I have new doubts.

Best Regards,

Martin