Question
Not able to read from an external EEPROM
Posted on July 10, 2018 at 17:05
I'm trying to write and read from an external
http://ww1.microchip.com/downloads/en/DeviceDoc/20001749K.pdf
. The datasheet states that I need to send an Enable code before I do anything. There is a start bit (SB) followed by an opcode, then a 6-bit address and then the actual data. I've combined the SB and opcode into one byte that I can send as a start condition. I'm able to enable, erase and then write to the EEPROM. I'm assuming this is working since the status returns HAL_OK and I can see the valid waveforms on the scope. What I can't seem to do is read the data back. For the READ operation I don't see any waveforms on the scope.Here is the main code:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration----------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_SPI1_Init();
/* USER CODE BEGIN 2 */
__HAL_SPI_ENABLE(&hspi1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
HAL_GPIO_WritePin(CS_GPIO_Port, CS_Pin, GPIO_PIN_SET);
HAL_Delay(10);
enable_status = Enable_EEPROM(&EEPROM_SPI_PORT);
HAL_Delay(10);
erase_status = Erase_EEPROM(&EEPROM_SPI_PORT, addr);
HAL_Delay(10);
write_status = Write_EEPROM(&EEPROM_SPI_PORT, addr, tx_data);
HAL_Delay(10);
read_status = Read_EEPROM(&EEPROM_SPI_PORT, addr, rx_data);
HAL_Delay(10);
HAL_GPIO_WritePin(CS_GPIO_Port, CS_Pin, GPIO_PIN_RESET);
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN
}
/* USER CODE END 3 */
}
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SPI_HandleTypeDef hspi1;
/* SPI1 init function */
void MX_SPI1_Init(void)
{
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_MASTER;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_16BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_64;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?And here is how the Enable, Erase, Read and Write functions of the EEPROM are written.
#define ERASE0x07 // erase specific memory location. This is followed by the 8-bit address and then by the 16-bit data.
#define READ0x06 // read the memory location.
#define WRITE0x05 // write to the memory location
#define EEPROM_SPI_PORT hspi1
extern SPI_HandleTypeDef EEPROM_SPI_PORT;
uint8_t Enable_EEPROM (SPI_TypeDef *spi_handle) {
uint16_t ewen = (0x04 << 8) | 0b00110000;
if (HAL_SPI_Transmit(spi_handle, &ewen, 1, HAL_MAX_DELAY) == HAL_OK) return TRUE;
else return FALSE;
}
uint8_t Erase_EEPROM (SPI_TypeDef *spi_handle, uint8_t addr) {
uint16_t write_package;
write_package = (ERASE << 8 | addr);
if (HAL_SPI_Transmit(spi_handle, &write_package, 1, HAL_MAX_DELAY) == HAL_OK) return TRUE;
else return FALSE;
}
uint8_t Write_EEPROM (SPI_TypeDef *spi_handle, uint8_t addr, uint16_t data) {
uint16_t write_package[2];
write_package[0] = (WRITE << 8 | addr);
write_package[1] = data;
if (HAL_SPI_Transmit(spi_handle, write_package, 2, HAL_MAX_DELAY) == HAL_OK) return TRUE;
else return FALSE;
}
uint8_t Read_EEPROM (SPI_TypeDef *spi_handle, uint8_t addr, uint16_t data) {
uint16_t write_package;
write_package = (READ << 8 | addr);
if (HAL_SPI_TransmitReceive(spi_handle, &write_package, &data, 1, HAL_MAX_DELAY) == HAL_OK) return TRUE;
else return FALSE;
}
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