[En-Nut-Discussion] Bug Fix for SpiMemRead, Ethernut 2, Data Flash reading.

[Brett Abbott]

Hi

re: Ethernut 2 Data Flash.  Unreliable reading of data in some scenarios.

For those few people who use SpiMemRead, there is a fix which may be 
required.  Ive ported it to ICCAVR and found unreliable use until I 
added the "8 dont care" bits referred to in the data spec.

Replacement code below.  Hope it helps.

Cheers
Brett


int SpiMemRead(u_short page, u_char *data, u_short len)
{

    // Main Memory Page to Buffer Transfer
    // 0x53, followed by 4 reserved, 11 address, 9 dont care
    //              0x53, 0000xxxx xxxxxxx0 00000000
   
    // Buffer Read: 0x54, followed by 15reserved (0), 9 address 
(pagenum), 8 dont care
    //              0x54, 00000000 0000000x xxxxxxxx 00000000
   
   
//    u_char buf_cmd[] = { 0x54, 0, 0, 0 };  // Original line
    u_char buf_cmd[] = { 0x54, 0, 0, 0, 0 }; // Added 5th byte, Brett 
Abbott, 14Apr06

    sbi(SPIMEM_CS_PORT, SPIMEM_CS_BIT);

    SpiByte(0x53);
    SpiByte(page >> 7);
    SpiByte(page << 1);
    SpiByte(0x00);

    cbi(SPIMEM_CS_PORT, SPIMEM_CS_BIT);

    while((SpiMemStatus() & 0x80) == 0);

    sbi(SPIMEM_CS_PORT, SPIMEM_CS_BIT);

    SpiWrite(buf_cmd, sizeof(buf_cmd));
    SpiRead(data, len);

    cbi(SPIMEM_CS_PORT, SPIMEM_CS_BIT);

    return 0;
}

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Brett Abbott, Managing Director, Digital Telemetry Limited
Email: Brett.Abbott at digital-telemetry.com
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