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TMS320F2800157: Sending 24-bit address to SPI EEPROM

John Treubig
Prodigy 120 points

Part Number: TMS320F2800157
Other Parts Discussed in Thread: C2000WARE

Hi,

I used the SPI EEPROM example in C2000Ware 5.04  to develop the code below to read from my EEPROM which uses 24-bit addressing.  The code below sends out the 24-bit address, but if I try to address anything over 255 (8 bits) the bit pattern on the SPI bus is incorrect (viewing from a scope) and I get an error.

Any insight will be helpful!

// Function to read data from the EEPROM
// - address is the byte address of the EEPROM
// - data is a pointer to an array of data being received
// - length is the number of characters in the array to receive
void PR_ReadData(uint32_t address, uint16_t *data, uint16_t length, uint16_t txdly)
{
     uint32_t RXdata = 0;
     CS_LOW;

    // Send the READ opcode.
    SPI_transmitByte(SPIA_BASE, READ);

    // Send EEPROM 24bit address to write data
    SPI_transmitByte(SPIA_BASE, address>>16);
    SPI_transmitByte(SPIA_BASE, address>>8);
    SPI_transmitByte(SPIA_BASE, address);

    // Receive length number of bytes
    SPI_receiveNBytes(SPIA_BASE, data, length, txdly);

     CS_HIGH;
}
  • 0
    TI__Mastermind 18495 points

    Hi John,

    Let me get back to you on this tomorrow.

    Best Regards,

    Aishwarya

  • 0 in reply to Aishwarya Rajesh
    Prodigy 120 points

    Thanks and I can save you the trouble as the fix is in feeding the address a byte at a time for SPI_transmitByte.

    // Function to read data from the EEPROM
// - address is the byte address of the EEPROM
// - data is a pointer to an array of data being received
// - length is the number of characters in the array to receive
void PR_ReadData(uint32_t address, uint16_t *data, uint16_t length, uint16_t txdly)
{
     uint32_t RXdata = 0;
     CS_LOW;

    // Send the READ opcode.
    SPI_transmitByte(SPIA_BASE, READ);

    // Send EEPROM 24-bit address to read data. The call must be fed a byte at a time
    SPI_transmitByte(SPIA_BASE, (address>>16) & 0xFF);
    SPI_transmitByte(SPIA_BASE, (address>>8) & 0xFF);
    SPI_transmitByte(SPIA_BASE, address & 0xFF);

    // Receive length number of bytes
    SPI_receiveNBytes(SPIA_BASE, data, length, txdly);

     CS_HIGH;
}