How to have more than one access to a USB pendrive using STM32L496ZG as USB host

[HABIJ.1]

Hello,

I am trying to write data in .txt file on a USB pendrive at a certain frequency (in the while 1 loop) using STM32L496ZG as the USB host in the Mass Storage Class (MSC) configuration.

I succeded writing to the .txt file in the first iteration, but after I can't access the USB pendrive anymore. I investigated the matter and I found out that when accessing the USB pendrive in the first iteration, the MSC_Handle->State is put to MSC_IDLE (see code below).

static USBH_StatusTypeDef USBH_MSC_Process(USBH_HandleTypeDef *phost)
{
 MSC_HandleTypeDef *MSC_Handle = (MSC_HandleTypeDef *) phost->pActiveClass->pData;
 USBH_StatusTypeDef error = USBH_BUSY;
 USBH_StatusTypeDef scsi_status = USBH_BUSY;
 USBH_StatusTypeDef ready_status = USBH_BUSY;
 
 switch (MSC_Handle->state)
 {
 case MSC_INIT:
 
 if (MSC_Handle->current_lun < MSC_Handle->max_lun)
 {
 .... // initialization of the MSC
 }
 
 //MSC initialization finished
 else // if (MSC_Handle->current_lun >= MSC_Handle->max_lun) where max_lun =1
 {
 MSC_Handle->current_lun = 0U;
 MSC_Handle->state = MSC_IDLE; //MSC put to IDLE
 phost->pUser(phost, HOST_USER_CLASS_ACTIVE); //access to the USB
 }
 break;
 
 

In the MSC_IDLE state, we can't access anymore the USB pendrive.

 case MSC_IDLE:
 error = USBH_OK;
 break;

I tried finding where to put the MSC_Handle->State back to MSC_INIT but with no success.

May anyone has a clue to share?

Tell me if more details, on what I did, is needed.

Thanks in advance for your help