FDCAN_CCCR.Init bit is not getting cleared STM32H723ZG

[Arrhenius]

Hi,

I am trying to initialize FDCAN for my project.

After the initialization I am clearing INIT bit in CCCR Register. The output what I can see is only CCE bit gets cleared but INIT bit is stuck at 1.

Below is my code snippet.

void Can_driver_init (void)

{

uint32_t StartAddress_l_u32 = CAN_RAM_OFFSET_CFG;

uint32_t RAMcounter_l_u32  = 0;

uint32_t ElementSize_l_u32 = (CAN_DATA_BYTES_CFG/4);

// Enable the peripheral clock for FDCAN

RCC->APB1HENR |= RCC_APB1HENR_FDCANEN;

// Exit from Sleep mode */

CAN->CCCR  &= ~FDCAN_CCCR_CSR;

// Wait till the CSR bit is set in CCCR */

while (CAN->CCCR == FDCAN_CCCR_CSR); // Wait timeout to be added

// Request initialization */

CAN->CCCR  |= FDCAN_CCCR_INIT;

// Wait until the INIT bit in CCCR register is set */

while ((CAN->CCCR & FDCAN_CCCR_INIT) != FDCAN_CCCR_INIT); // Wait timeout to be added

// Enable configuration change */

CAN->CCCR  |= FDCAN_CCCR_CCE;

// Enable automatic retransmission */

CAN->CCCR  &= ~FDCAN_CCCR_DAR;

// Disable transmit pause */

CAN->CCCR  &= ~FDCAN_CCCR_TXP;

// Disable Protocol Exception Handling */

CAN->CCCR  &= ~FDCAN_CCCR_PXHD;

// Set CAN Frame Format as CLASSIC*/

CAN->CCCR  |= CAN_FRAME_CFG;

// Configure CAN Operation Mode as normal */

CAN->CCCR  |= CAN_MODE_CFG;

// Set the nominal bit timing register for CAN Bit-rate*/

CAN->NBTP  = (NBTP_NSJW_VAL_CFG  << FDCAN_NBTP_NSJW_Pos)  |

  (NBTP_NTSEG1_VAL_CFG << FDCAN_NBTP_NTSEG1_Pos) |

  (NBTP_NTSEG2_VAL_CFG << FDCAN_NBTP_NTSEG2_Pos) |

  (NBTP_NBRP_VAL_CFG  << FDCAN_NBTP_NBRP_Pos);

// Configure number of dedicated transmit buffers. */

CAN->TXBC   = (NBR_OF_TXBUFFER_CFG << FDCAN_TXBC_NDTB_Pos);

// Configure Tx buffer element size */

CAN->TXESC  |= (ElementSize_l_u32 << FDCAN_TXESC_TBDS_Pos);//TBD

// Configure Rx buffer element size */

CAN->RXESC  |= (ElementSize_l_u32 << FDCAN_RXESC_RBDS_Pos);

//--------------------------------------------------------------------

//--------------------------------------------------------------------

 // Message RAM configuration:

 // ***************************

 //      ________

 //   0x00 |________| Standard_filter[0]

 //     |________|

 //     |________|

 //      |||||||||| Rx_buffer[0]

 //      ||||||||||

 //      |||||||||| Rx_buffer[n]

 //      |________| Tx_buffer[0]

 //      |________|

 //      |________| Tx_buffer[n]

 //      ||||||||||

 //      ||||||||||

 //      |||||||||| FreeSpace

 //      ||||||||||

 //      ||||||||||

 //  @2560 ||||||||||

// Calculate each RAM block address

// -------------------------------

//  Block 0: Standard Filters

// -------------------------------

// Standard filter list start address

CAN->SIDFC  |= (StartAddress_l_u32 << FDCAN_SIDFC_FLSSA_Pos);

// Number of standard filter elements

CAN->SIDFC  |= (NBR_OF_STD_FILTERS << FDCAN_SIDFC_LSS_Pos);

StartAddress_l_u32 += NBR_OF_STD_FILTERS;

// -------------------------------

//  Block 1: Dedicated Rx Buffers

// -------------------------------

// Rx buffer list start address */

CAN->RXBC  |= (StartAddress_l_u32 << FDCAN_RXBC_RBSA_Pos);

StartAddress_l_u32 += (NBR_OF_RXBUFFER_CFG * CAN_DATA_BYTES_CFG);

// Note: No register field is defined for declaring

// number of dedicated Rx buffers in STM32H7

// -------------------------------

//  Block 2: Dedicated Tx Buffers

// --------------------------------

// Tx buffer list start address */

CAN->TXBC  |= (StartAddress_l_u32 <<FDCAN_TXBC_TBSA_Pos);

// Number of dedicated Tx buffers */

CAN->TXBC  |= (NBR_OF_TXBUFFER_CFG << FDCAN_TXBC_NDTB_Pos);

//--------------------------------

//--------------------------------

// Store the Addresses of different fields of CAN Message RAM

MsgRam.StandardFilterSA = SRAMCAN_BASE;

MsgRam.RxBufferSA    = MsgRam.StandardFilterSA + (NBR_OF_STD_FILTERS * 4);

MsgRam.TxBufferSA    = MsgRam.RxBufferSA + (NBR_OF_RXBUFFER_CFG * (CAN_DATA_BYTES_CFG * 4));

MsgRam.EndAddress    = MsgRam.TxBufferSA + (NBR_OF_TXBUFFER_CFG * (CAN_DATA_BYTES_CFG * 4));

  // Flush the allocated Message RAM area

for (RAMcounter_l_u32 = MsgRam.StandardFilterSA; RAMcounter_l_u32 < MsgRam.EndAddress; RAMcounter_l_u32 += 4U)

{

*(uint32_t *)(RAMcounter_l_u32) = 0x00000000;

}

/*--------------------------------------------------------------------

 *--------------------------------------------------------------------*/

// Configure filter elements

CanIf_filterInit();

// Enable the interrupts

Can_driver_enableInterrupts();

  // Request leave initialization

CAN->CCCR  &= ~FDCAN_CCCR_INIT;

}

[BHend.2]

I am having the same issue with the INIT bit not clearing - did this get resolved?

[KJona.2]

Hi,

Any updates?

I am having the same issue but on STM32G431KBT6. I am using arm non eabi toolchain, assembly and cmsis copied from cube project + cmake.

I observed that the ARA bit is set just after enabling fdcan in rcc. The code to reproduce the issue:

 RCC->APB1ENR1 |= RCC_APB1ENR1_FDCANEN;  

 FDCAN1->CCCR |= FDCAN_CCCR_INIT;

//here the ARA bit =1

while ((FDCAN1->CCCR & FDCAN_CCCR_INIT) != FDCAN_CCCR_INIT); 

That happens only when using cmake to build target. I created a new empty project in STM32 cube IDE and added mentioned lines:

void main()

{

 RCC->APB1ENR1 |= RCC_APB1ENR1_FDCANEN;  

 FDCAN1->CCCR |= FDCAN_CCCR_INIT;

//here the ARA bit =1

while ((FDCAN1->CCCR & FDCAN_CCCR_INIT) != FDCAN_CCCR_INIT); 

}

The issue did not occur. I must not be doing something that STM32 Cube IDE is. I spent a lot of time trying to debug this issue...

Any ideas?

I found that somebody have the same issue:

STM32H743 FDCAN stuck in init mode - General Discussion - PlatformIO Community

[Lorenzo5]

Hello community

A little up for this subject because I have the same problem...

Does someone has any idea?