TCAN4550EVM: Trouble in establishing communication to TCAN4550EVM with STM32F407VET6

Hello,

I am trying to connect TCAN4550EVM to my STM32F407VET6 board and I'm stuck in the first step. I can't even read the device ID correctly. What I got from address 'h000 & 'h0004 are random values.

I'm able to use USART and COM function and read the device id of a flash memory on my MCU board, so the MCU itself is not broken. 

The compiler I'm using is Keil V5 Lite. The code sample on the website seems to be for other compiler and MCU so I cannot use it directly. I simplified my code to SPI-related and hope someone could check out anything wrong. I have very limited experience in MCU application. Maybe they are simple mistakes.

I set the SPI frequency to 10MHz(APB clock is 80Mhz), CPHA=0, CPOL=0. Only 6 wires are connected: VBAT and GND to a 12V power supply, SCLK to PA5, SDI to PA7, SDO to PA6, nCS to PA4.

void SPISendByte(unsigned char tmpData)
{
	while((SPI1->SR&2)==0);		//wait for TXE
	SPI1->DR = tmpData;
}
unsigned char SPIGetByte()
{
	while((SPI1->SR&2)==0);		//wait for TXE
	while(SPI1->SR&(1<<7));		//wait for !BSY
	SPI1->DR = 0;		//send dummy data
	while(!(SPI1->SR&1));		//wait for RXNE
	return SPI1->DR;
}

void TCANReadBytes(unsigned short address, unsigned char *tmpC, unsigned short len1)
{
	GPIOA->BSRRH |= GPIO_Pin_4;		//set to 0, enable
	SPISendByte(0x41);		//read
	SPISendByte(address>>8);		//MSB
	SPISendByte(address&0xFF);		//LSB
	SPISendByte(len1);		//len1*32bit
	while((SPI1->SR&2)==0);		//wait for TXE
	while(SPI1->SR&(1<<7));		//wait for !BSY
	SPI1->DR;		//read the last dummy byte
	for (unsigned short idx1=0; idx1<len1*4; ++idx1)
		tmpC[idx1] = SPIGetByte();
	GPIOA->BSRRL |= GPIO_Pin_4;		//set to 1, disable
}

int main(void)
{
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	USART1_Init(115200);

	//SPI settings
	RCC->AHB1ENR |= RCC_AHB1Periph_GPIOA;
	GPIO_InitTypeDef GPIO_InitStructure;

	GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_4;		//nCS
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_OUT;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	GPIOA->BSRRL |= GPIO_Pin_4;		//set to 1, disable NCS
	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
	
	RCC->APB2ENR |= (1<<12);		//enable SPI1 clock
	SPI1->CR1 |= 0 << 0;		//CPHA = 0
	SPI1->CR1 |= 0 << 1;		//CPOL = 0
	SPI1->CR1 |= 1 << 2;		//master mode
	SPI1->CR1 |= 2 << 3;		//baudrate = fPCLK /8
	SPI1->CR1 |= 0 << 7;		//MSB first
	SPI1->CR1 |= 1 << 9;		//software slave management
	SPI1->CR1 |= 1 << 8;		//software slave internal
	SPI1->CR1 |= 0 << 10;		//RXonly =0, full-duplex
	SPI1->CR1 |= 0 << 11;		//frame format: 8 bit data
	SPI1->CR1 |= 1 << 6;		//enable external
	
	unsigned char tmpC[5];
	tmpC[4] = 10;
	for(int idx1=0;idx1<8;idx1=idx1+4)
	{
		tmpC[0] = 0;
		tmpC[1] = 0;
		tmpC[2] = 0;
		tmpC[3] = 0;
		TCANReadBytes(idx1, tmpC, 1);
		USART1SendChar((char*)tmpC, 5);		//send the response to PC via COM port
	}

	while (1)
	{
	}
}

The responses are
[2023-07-20 10:43:10.502]# RECV HEX>
00 00 00 00 0A C0 7F F2 40 0A
[2023-07-20 10:43:12.824]# RECV HEX>
FF FF EA 00 0A 02 00 00 00 0A
[2023-07-20 10:43:15.247]# RECV HEX>
FF FF 92 00 0A 02 00 00 00 0A
[2023-07-20 10:43:17.708]# RECV HEX>
FF FF F5 40 0A 02 00 00 00 0A
[2023-07-20 10:43:20.001]# RECV HEX>
FF FF 92 00 0A 00 00 00 00 0A
[2023-07-20 10:43:23.255]# RECV HEX>
00 00 00 00 0A 00 00 00 52 0A
[2023-07-20 10:43:25.510]# RECV HEX>
FF FF 89 00 0A 00 01 39 05 0A
[2023-07-20 10:43:27.581]# RECV HEX>
00 00 00 00 0A 00 00 00 00 0A
[2023-07-20 10:43:29.656]# RECV HEX>
00 00 00 00 0A 00 00 00 00 0A
[2023-07-20 10:43:31.665]# RECV HEX>
00 00 00 00 0A 00 00 00 00 0A
[2023-07-20 10:43:33.786]# RECV HEX>
00 00 00 00 0A 00 00 00 00 0A
[2023-07-20 10:43:35.888]# RECV HEX>
00 00 00 00 0A 00 00 00 00 0A
[2023-07-20 10:43:38.188]# RECV HEX>
7F FF FF FF 0A C4 80 00 00 0A
[2023-07-20 10:43:40.176]# RECV HEX>
FF FF 92 00 0A 00 01 39 05 0A

I tried to read the TCAN ID during the start of MCU and tested it with the reset button of MCU board.