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With an STM32 bit microcontroller, I am working on an EEPROM interface. I'm using STMCUBEIDE and proteus software to simulate hardware for the same purpose. The following is my code:

HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);


uart_buf_len = sprintf(uart_buf, "SPI Test Begin\r\n");
HAL_UART_Transmit(&huart1, (uint8_t *)uart_buf, uart_buf_len, 100);


HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)&EEPROM_WREN, 1, 100);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);

spi_buf[0] = 0x01;
spi_buf[1] = 0x02;
spi_buf[2] = 0x03;


addr = 0x05;


HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)&EEPROM_WRITE, 1, 100);
HAL_SPI_Transmit(&hspi1, (uint8_t *)&addr, 1, 100);
HAL_SPI_Transmit(&hspi1, (uint8_t *)spi_buf, 3, 100);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);


spi_buf[0] = 0;
spi_buf[1] = 0;
spi_buf[2] = 0;


wip = 1;
while (wip)
{
  
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);
  HAL_SPI_Transmit(&hspi1, (uint8_t *)&EEPROM_RDSR, 1, 100);
  HAL_SPI_Receive(&hspi1, (uint8_t *)spi_buf, 1, 100);
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);

  
  wip = spi_buf[0] & 0b00000001;
}


HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);
HAL_SPI_Transmit(&hspi1, (uint8_t *)&EEPROM_READ, 1, 100);
HAL_SPI_Transmit(&hspi1, (uint8_t *)&addr, 1, 100);

HAL_SPI_Receive(&hspi1, (uint8_t *)spi_buf, 3, 100);
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);


uart_buf_len = sprintf(uart_buf,
                        "0x%02x 0x%02x 0x%02x\r\n",
                        (unsigned int)spi_buf[0],
                        (unsigned int)spi_buf[1],
                        (unsigned int)spi_buf[2]);
HAL_UART_Transmit(&huart1, (uint8_t *)uart_buf, uart_buf_len, 100);

I am reusing code given in https://www.digikey.in/en/maker/projects/getting-started-with-stm32-how-to-use-spi/09eab3dfe74c4d0391aaaa99b0a8ee17

I am facing following issue:

If I start at address 0x05 and write three bytes with the data sequence 01, 02, 03, and then retrieve the data from that address, I get 02, 03, and ff. However, if I read data from address 0x04, I can read the exact sequence that I just wrote in the writing portion.

Rikin Nayak
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    What EEPROM chip are you trying to use? They aren't all identical - in particular, the number of address bytes you have to send with a read or write command depends on the chip's capacity. The code you show here cannot possibly work with an EEPROM with more than 256 bytes, as you're only sending one address byte. – jasonharper Aug 03 '22 at 04:53

0 Answers0