PIC16LF1902-I/P View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
PIC16LF1902-I/P
Microchip Technology
PIC16LF1902-I/P Datasheet PDF : 236 Pages
| |||
PIC16LF1902/3
10.2.3
ERASING FLASH PROGRAM
MEMORY
While executing code, program memory can only be
erased by rows. To erase a row:
1. Load the PMADRH:PMADRL register pair with
the address of new row to be erased.
2. Clear the CFGS bit of the PMCON1 register.
3. Set the FREE and WREN bits of the PMCON1
register.
4. Write 55h, then AAh, to PMCON2 (Flash
programming unlock sequence).
5. Set control bit WR of the PMCON1 register to
begin the erase operation.
See Example 10-2.
After the “BSF PMCON1,WR” instruction, the processor
requires two cycles to set up the erase operation. The
user must place two NOP instructions after the WR bit is
set. The processor will halt internal operations for the
typical 2 ms erase time. This is not Sleep mode as the
clocks and peripherals will continue to run. After the
erase cycle, the processor will resume operation with
the third instruction after the PMCON1 write instruction.
EXAMPLE 10-2: ERASING ONE ROW OF PROGRAM MEMORY
; This row erase routine assumes the following:
; 1. A valid address within the erase row is loaded in ADDRH:ADDRL
; 2. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM)
BCF
BANKSEL
MOVF
MOVWF
MOVF
MOVWF
BCF
BSF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP
BCF
BSF
INTCON,GIE
PMADRL
ADDRL,W
PMADRL
ADDRH,W
PMADRH
PMCON1,CFGS
PMCON1,FREE
PMCON1,WREN
55h
PMCON2
0AAh
PMCON2
PMCON1,WR
PMCON1,WREN
INTCON,GIE
; Disable ints so required sequences will execute properly
; Load lower 8 bits of erase address boundary
; Load upper 6 bits of erase address boundary
; Not configuration space
; Specify an erase operation
; Enable writes
; Start of required sequence to initiate erase
; Write 55h
;
; Write AAh
; Set WR bit to begin erase
; Any instructions here are ignored as processor
; halts to begin erase sequence
; Processor will stop here and wait for erase complete.
; after erase processor continues with 3rd instruction
; Disable writes
; Enable interrupts
DS41455A-page 82
Preliminary
2011 Microchip Technology Inc.
Share Link: 