EEPROM SPI Reading issue

[Siva21]

Hello, 

I am trying to write and read from stm32f105 to an eeprom 93AA46A, using Full-Duplex Master. 

To write into the eeprom, I am using following code:

void EEPROM_WriteEnable(void)
{
    uint8_t cmd = EEPROM_CMD_WRITE_ENABLE; //0x98

    EEPROM_CS_HIGH();
    HAL_Delay(1);

    HAL_SPI_Transmit(&hspi1, &cmd, 1, HAL_MAX_DELAY);

    EEPROM_CS_LOW();
}
void EEPROM_WriteByte(uint8_t address, uint8_t data)
{
    uint8_t txData[3];
    // Enable Write Operation
    EEPROM_WriteEnable();

    // Prepare Write Command (101xxxxx | 6-bit address)
	txData[0] = EEPROM_CMD_WRITE; //0xA0
	txData[1] = 0x00;  //address
	txData[2] = 0x55;  // Data

	// Send Write Command
	EEPROM_CS_HIGH();
	HAL_Delay(1);

	HAL_SPI_Transmit(&hspi1, txData, 3, HAL_MAX_DELAY);

	EEPROM_CS_LOW();
}

and to read from EEPROM, I have follwoing code:

void EEPROM_ReadByte(uint8_t address)
{
uint8_t txData_read[3];
uint8_t rxData = 0;

	txData_read[0] = EEPROM_CMD_READ; //0xC0
	txData_read[1] = 0x00; //address
	txData_read[2] = 0x01; // dummy

    EEPROM_CS_HIGH();
    HAL_Delay(1);
    HAL_SPI_Transmit(&hspi1, txData_read, 3, HAL_MAX_DELAY);

    HAL_SPI_Receive(&hspi1, rxData, 1, HAL_MAX_DELAY);

    EEPROM_CS_LOW();
}

I don't get anything from eeprom, the HAL_SPI_Receive doesn't make anything. Is there anyone that can verify that the code is correct?

Thank you.

[Andrew Neil]

I think you mean oscilloscope - not oscillator?

Doesn't your 'scope have a means to capture screenshots?

As @mƎALLEm said earlier, have you checked this against the EEPROM specs - particular for frequency & SPI Mode?

[Siva21]

The eeprom is powered by 3.3V now. It was a mistake which it is fixed now. 

[mƎALLEm]

You still not answered the question: what is the GPIO used for EEPROM DO? If it was not FT it could be damaged.

[Siva21]

Do you make fun of me? Just forget my post. 

Very bad support. 

[bmckenney · Accepted solution]

The datasheet I see for the 93AA46A says it's a Microwire device. Microwire is kind of a first-cousin to SPI.

In particular, the request [Ref Table 1-4] is 10 bits, not 8: {1-bit Start, 2-bits Op-code, 7-bits Address}. The Read/Write data is in units of 8-bits. Microwire has no objection to this, but the STM32F105 [Ref RM0008] only supports 8/16-bits, and I don't think I've seen an STM32 where the Rx and Tx frame sizes can be different. (RM0008 also doesn't mention Microwire.)

You may want to consider bit-banging. (There are only 128 bytes, so speed probably isn't a big deal.)

Also: In

> HAL_SPI_Receive(&hspi1, rxData, 1, HAL_MAX_DELAY);

 I expect you meant

> HAL_SPI_Receive(&hspi1, &rxData, 1, HAL_MAX_DELAY);

I'm a bit surprised the compiler didn't object.

[Edit: Fixed some minor specifics. The principle is the same.]

[mƎALLEm]

Unfortunately and according to your schematics, EEPROM DO is connected to PA6 which is not FT IO:

Most probably it was broken while you powered your EEPROM with 5V!

[Siva21]

Thank you @bmckenney 

I have implemented bit-banging for SPI, and it works fine now.