16.14 Quad Double Word Programming

The process for Quad Double Word programming is identical to Word programming except that all eight of the NVMDATAx registers are used. The value of the NVMDATA0 register is programmed at address NVMADDR and so on. Refer to the following code example for details.

Always perform the Quad Double Word programming on a Quad Double Word boundary so the user can ignore the NVMADDR address bits 3 through 0.

Quad Double Word programming only succeeds, if the target address is in a page that is not write-protected. If programming a Quad Double Word, erase it before programming any word in it again, even if changing a bit from an erased ‘1’ state to a ‘0’ state.

The value of 0x11111111 is programmed into location 0x1008000 and so on. Refer to the following code example for details.

The following example code provides details about the Quad Double Word programming.

Quad Double Word Programming Code Example:

…

// Set up Address and Data Registers
    NVMADDR  = 0x1008000;      // physical address
    NVMDATA0 = 0x11111111;     // value written to 0x1008000
    NVMDATA1 = 0x22222222;     // value written to 0x1008004
    NVMDATA2 = 0x33333333;     // value written to 0x1008008
    NVMDATA3 = 0x44444444;     // value written to 0x100800C
    NVMDATA4 = 0x55555555      // value written to 0x1008010
    NVMDATA5 = 0x66666666      // value written to 0x1008014
    NVMDATA6 = 0x77777777      // value written to 0x1008018
    NVMDATA7 = 0x88888888      // value written to 0x100801C

// set the operation, assumes WREN = 0
    NVMCONbits.NVMOP = 0x2;    // NVMOP for Quad Double Word programming

// Enable Flash for write operation and set the NVMOP 
    NVMCONbits.WREN = 1;

// Start programming
    NVMInitiateOperation();    // see Initiate NVM Operation (Unlock Sequence Example)

// Wait for WR bit to clear
    while(NVMCON & NVMCON_WR);

// Disable future Flash Write/Erase operations
    NVMCONbits.WREN = 0;

// Check Error Status
    if(NVMCON & 0x3000)    // mask for WRERR and LVDERR bits