Errors in SDMMC (STA and IDMABSIZE) registers / STM32cubIDE SFRs for STM32L4R9 ?

[gorgabab]

Hello

A few days ago, I went through the SDMMC registers using stm32l4r9-discovery.
I am using the "June 2021 RM0432 Rev 9" and haven't found a more recent datasheet for it.

Using stm32cubeide (1.17.0) (window->show view->)SFRs panel, the bits shown in SDMMC1 STA don't match with the datasheet ones in 54.10.11 SDMMC_STAR section as follow. The IDMA labels are missing too in SFRs.

In 54.10.17 (p. 2030/3000), the IDMABNDT attribute is defined for the [12:5] bits (8-bit long value).
On the bit table, the 16th bit is shown as "rw" which is false as the [31:13] are specified as "reserved, must be kept at reset value". (In some stm32 boards, the sdmmc IDMABNDT is defined on [5:16] bits so it just might be a copy-paste error).

My main concerns about this register are the differences between the datasheet and HAL function.

The datasheet specifies a constant bit offset 5 for IDMABNDT, but in the HAL function, the IDMABSIZE is set depending on the BLOCKSIZE (constant 512 bytes) which is unclear/confusing to me.

Let's say My IDMA buffers are 10-block long.
Using datasheet, we have

SDMMC1->IDMABSIZE = ((SDMMC1->IDMABSIZE & 0xffffe01f) | (10 << 5)); // 0xffffe01f is the mask to prevent writes outside [12:5] // value is 8-bit long value
// = 320UL

Using HAL_SDEx_ConfigDMAMultiBuffer, we have

SDMMC1->IDMABSIZE = (uint32_t) (BLOCKSIZE * 10);
// = 5120UL (12 bits long starting to 0 which means a larger number of block would exceed the initial mask [12:5])

The results differ. My tests using the datasheet method worked but not the HAL ones where IDMABSIZE register would still be stuck at 0 after initialization (the mask might block the operation or something), thus blocking the HAL_SDEx_WriteBlocksDMAMultiBuffer operation.

[KDJEM.1 · Accepted solution]

Hello @gorgabab,

Thank you for bringing this issue to our attention. I reported this internally.

Internal ticket number: 202191 (This is an internal tracking number and is not accessible or usable by customers) 

Thank you for your contribution in STCommunity.

Kaouthar

[gorgabab]

Hello,

Thank you for your answer.
Having forgotten about my post, I also forgot to correct an element concerning the IDMABSIZE thing.

I think I was partially wrong about my example.

Let's say my IDMA buffers are 10-block long.

Using HAL_SDEx_ConfigDMAMultiBuffer, we have :

IDMABSIZE = 10 * BLOCKSIZE; // = 5120 // byte long buffer, BLOCKSIZE not editable by user

Using the datasheet, we would take our buffer size (10 * my_blocksize) and convert it to fit the IDMABNDT 8-bit slot.
So we would have (in case of my_blocksize = 512) :

int my_blocksize = 512; // used for SDMMC CTRL reg DBLOCKSIZE config & can be changed
IDMABSIZE = (10 * 512 / 8 / 4) << 5; // = 5120 // ("/8/4" from the small explanation in IDMABDNT).

The HAL config is equivalent to the register manual config in the case of my_blocksize = BLOCKSIZE = 512 bytes.
However, the 2 methods should differ if we set a different blocksize value (my_blocksize =/= BLOCKSIZE).

The confusion also lies here :
The user can change the block size through sdmmc command (register CTRL ; DBLOCKSIZE). But the user cannot change the BLOCKSIZE constant of 512 bytes used in HAL libs, parameter that also cannot be changed in CUBEMX (only in optional FatFS / FileX).

Also, the HAL_SDEx_ConfigDMAMultiBuffer doesn't mention an idma buffer size limit which could led to errors if the user doesn't have a look in the datasheet (max size is 255 * 8 * 4 = 8160 bytes).

(I was wrong once, I can be wrong twice lol)