2.5 Erasing Program Memory

Figure 2-5 shows a high-level overview of the Bulk Erase of code memory.

Table 2-4 provides the ICSP programming process for erasing the program memory.

Note: Program memory must be erased before writing any data to program memory.

Figure 2-5. Bulk Erase Flow

Table 2-4. Serial Instruction Execution for Bulk Erase of Code Memory
Command (Binary)	Data (Hex)	Description
Step 1: Exit the Reset vector.
`0000` `0000` `0000` `0000` `0000` `0000` `0000`	`000000` `000000` `000000` `040200` `000000` `000000` `000000`	`NOP` `NOP` `NOP` `GOTO 0x200` `NOP` `NOP` `NOP`
Step 2: Set the NVMCON register to erase all user program memory.
`0000` `0000` `0000` `0000`	`2400EA` `88468A` `000000` `000000`	`MOV #0x400E, W10` `MOV W10, NVMCON` `NOP` `NOP`
Step 3: Initiate the erase cycle.
`0000` `0000` `0000` `0000` `0000` `0000` `0000` `0000`	`200551` `8846B1` `200AA1` `8846B1` `A8E8D1` `000000` `000000` `000000`	`MOV #0x55, W1` `MOV W1, NVMKEY` `MOV #0xAA, W1` `MOV W1, NVMKEY` `BSET NVMCON, #WR` `NOP` `NOP` `NOP`
Step 4: Generate clock pulses for the code memory Bulk Erase operation to complete until the WR bit is cleared.
`0000` `0000` `0000` `0000` `0000` `0001` `0000` `0000` `0000` `0000` `0000` `0000` `0000` —	`000000` `804680` `000000` `887E60` `000000` `<VISI>` `000000` `000000` `000000` `040200` `000000` `000000` `000000` —	`NOP` `MOV NVMCON, W0` `NOP` `MOV W0, VISI` `NOP` Clock out contents of the VISI register. `NOP` `NOP` `NOP` `GOTO 0x200` `NOP` `NOP` `NOP` Repeat until the WR bit is cleared.