TJ:
Given that polled mode works (and works in 4-bit mode too), I've not been looking too much for hardware issues. It would be a bit embarassing (but good) to find out it is a hardware issue of some kind. It is literally just eight wires with 47K pull-up resistors on CMD and the four data lines. No pull-up on CLK. That follows the example I've seen in some demo board schematics. I do have a scope, but just a 2-channel one (Tek TDS-210 60MHz). Signals look pretty good. There is a bit of ringing, but not bad enough to worry about.
The videos suggested by Bojan at the top are good. The link is to 1-bit and the next video is for 4-bit mode. That person strongly suggested downgrading to an older version of CubeMX, but that is a *really* old version now and release notes from ST since then say they fixed the issue he was addressing in the videos. I've started stepping through the code to see where things might not be going right, but DMAs are a bit new to me.
The code snippet is is a cut/paste from the STM32L4 Cube demos (STM32Cube_FW_L4_V1.13.0\Projects\STM32L4R9I-EVAL\Applications\FatFs\FatFs_uSD_DMA_Standalone) pasted into the CubeMX-generated code. and pasted below. Only mods are I commented out formatting step and for f_mount changed the last parameter to actually mount the drive to get the error sooner.
Your queries on it being hardware would make a tidy explanation and bears further study. If ST had an issue and explicitly fixed it, I would suspect it was reasonably well tested. If it were still broken, you think there would be others posting questions too and I couldn't find any.
will
/*##-0- Turn all LEDs off(red, green, orange and blue) */
HAL_GPIO_WritePin(GPIOG, (GPIO_PIN_10 | GPIO_PIN_6 | GPIO_PIN_7 |
GPIO_PIN_12), GPIO_PIN_SET);
/*##-1- FatFS: Link the SD disk I/O driver ##########*/
//retSD = FATFS_LinkDriver(&SD_Driver, SD_Path) ; /* Already called by MX_FATFS_Init. Calling twice is bad */
if(retSD == 0){
/* success: set the orange LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_7, GPIO_PIN_RESET);
/*##-2- Register the file system object to the FatFs module ###*/
res = f_mount(&SDFatFs, (TCHAR const*)SD_Path, 1) ;
if(res != FR_OK){
/* FatFs Initialization Error : set the red LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
while(1);
} else {
/*##-3- Create a FAT file system (format) on the logical drive#*/
/* WARNING: Formatting the uSD card will delete all content on the
device */
//if(f_mkfs((TCHAR const*)"", 0, 0) != FR_OK){
// /* FatFs Format Error : set the red LED on */
// HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
// while(1);
//} else
{
/*##-4- Create & Open a new text file object with write access#*/
if(f_open(&MyFile, "Hello.txt", FA_CREATE_ALWAYS | FA_WRITE) !=
FR_OK){
/* 'Hello.txt' file Open for write Error : set the red LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
while(1);
} else {
/*##-5- Write data to the text file ####################*/
res = f_write(&MyFile, wtext, sizeof(wtext), (void
*)&byteswritten);
if((byteswritten == 0) || (res != FR_OK)){
/* 'Hello.txt' file Write or EOF Error : set the red LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
while(1);
} else {
/*##-6- Successful open/write : set the blue LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_12, GPIO_PIN_RESET);
f_close(&MyFile);
/*##-7- Open the text file object with read access #*/
if(f_open(&MyFile, "Hello.txt", FA_READ) != FR_OK){
/* 'Hello.txt' file Open for read Error : set the red LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
while(1);
} else {
/*##-8- Read data from the text file #########*/
res = f_read(&MyFile, rtext, sizeof(wtext), &bytesread);
if((strcmp(rtext,wtext)!=0)|| (res != FR_OK)){
/* 'Hello.txt' file Read or EOF Error : set the red LED on */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_10, GPIO_PIN_RESET);
while(1);
} else {
/* Successful read : set the green LED On */
HAL_GPIO_WritePin(GPIOG, GPIO_PIN_6, GPIO_PIN_RESET);
/*##-9- Close the open text file ################*/
f_close(&MyFile);
}}}}}}}
/*##-10- Unlink the micro SD disk I/O driver #########*/
FATFS_UnLinkDriver(SD_Path);
