PIC16LF1508 Datasheet, PDF (105/384 Pages) Microchip Technology – 20-Pin Flash, 8-Bit Microcontrollers with nanoWatt XLP Technology

10.3 Modifying Flash Program Memory
When modifying existing data in a program memory
row, and data within that row must be preserved, it must
first be read and saved in a RAM image. Program
memory is modified using the following steps:
1. Load the starting address of the row to be
modified.
2. Read the existing data from the row into a RAM
image.
3. Modify the RAM image to contain the new data
to be written into program memory.
4. Load the starting address of the row to be
rewritten.
5. Erase the program memory row.
6. Load the write latches with data from the RAM
image.
7. Initiate a programming operation.
PIC16(L)F1508/9
FIGURE 10-7:
FLASH PROGRAM
MEMORY MODIFY
FLOWCHART
Start
Modify Operation
Read Operation
F(Figiguurere1x0.-x2)
An image of the entire row read
must be stored in RAM
Modify Image
The words to be modified are
changed in the RAM image
Erase Operation
F(Figiguurere1x0.-x4)
WRITE Operation
use RAM image
F(Figiugruere1x0.-x5)
End
Modify Operation
 2011 Microchip Technology Inc.
Preliminary
DS41609A-page 105