How to configure data transfer mode of uSDHC on mpc5748g?

[shingozhou]

Hi, 

  Data transfer modes are described in the chapter 49.2.1.2.1 of the MPC5748G Reference Manual. As mentioned there, how to configure one of these modes, such as SD 4-bit? There is not related function to configure it directly.

  Precondition: MPC5748G, S32DS for PA2.1, SDK PA RTM v3.0.0, freeRTOS.

BR,shingo

[lukaszadrapa]

Hi,

there's function uSDHC_DRV_SetDataBusWidth() which configures DTW bit field in uSDHC_PROT_CTRL register.

Regards,

Lukas

[shingozhou]

Hi, Lukas:

  Funtion uSDHC_DRV_SetDataBusWidth() just sets the buswidth,  cannot judge the data transfer mode.

take 4-bit for example, after using function uSDHC_DRV_SetDataBusWidth(INST_USDHC1, uSDHC_DATA_BUS_WIDTH_4BIT), which the data transfer mode of the uSDHC works on? SD 4-bit or MMC 4-bit ?

BR,shingo

[lukaszadrapa]

Hi,

it is up to the driver to recognize which card is connected. It's not necessary to do this manually by user.

Regards,

Lukas

[shingozhou]

Hi, Lukas:

  Thank you for your advice, but I have another question as follows: 

  If the MCU is connected to an external SD I/O card instead of an SD card or MMC card, in order to initialize the uSDHC module, which of the following two options should I choose?

 1. use the function uSDHC_Init() defined in the file "usdhc_impl.c".

 2. directly use a few simple library fucntions defined in the file "usdhc_driver.h", such as uSDHC_DRV_Init(), uSDHC_DRV_InstallCallback(), uSDHC_DRV_SetBusClock(), uSDHC_DRV_SetDataBusWidth().

 PS: precontion:S32_SDK_S32PA_RTM_3.0.0.

BR, shingo