Microchip Technology AC164337 Data Sheet
2006-2014 Microchip Technology Inc.
DS70000178D-page 83
dsPIC30F1010/202X
7.6
Programming Operations
A complete programming sequence is necessary for
programming or erasing the internal Flash in RTSP
mode. A programming operation is nominally 2 msec in
duration and the processor stalls (waits) until the oper-
ation is finished. Setting the WR bit (NVMCON<15>)
starts the operation, and the WR bit is automatically
cleared when the operation is finished.
programming or erasing the internal Flash in RTSP
mode. A programming operation is nominally 2 msec in
duration and the processor stalls (waits) until the oper-
ation is finished. Setting the WR bit (NVMCON<15>)
starts the operation, and the WR bit is automatically
cleared when the operation is finished.
7.6.1
PROGRAMMING ALGORITHM FOR
PROGRAM FLASH
PROGRAM FLASH
The user can erase and program one row of program
Flash memory at a time. The general process is:
Flash memory at a time. The general process is:
1.
Read one row of program Flash (32 instruction
words) and store into data RAM as a data
“image”.
words) and store into data RAM as a data
“image”.
2.
Update the data image with the desired new
data.
data.
3.
Erase program Flash row.
a)
Setup NVMCON register for multi-word,
program Flash, erase and set WREN bit.
program Flash, erase and set WREN bit.
b)
Write address of row to be erased into
NVMADRU/NVMDR.
NVMADRU/NVMDR.
c)
Write ‘55’ to NVMKEY.
d)
Write ‘AA’ to NVMKEY.
e)
Set the WR bit. This will begin erase cycle.
f)
CPU will stall for the duration of the erase
cycle.
cycle.
g)
The WR bit is cleared when erase cycle
ends.
ends.
4.
Write 32 instruction words of data from data
RAM “image” into the program Flash write
latches.
RAM “image” into the program Flash write
latches.
5.
Program 32 instruction words into program
Flash.
Flash.
a)
Setup NVMCON register for multi-word,
program Flash, program and set WREN bit.
program Flash, program and set WREN bit.
b)
Write ‘55’ to NVMKEY.
c)
Write ‘AA’ to NVMKEY.
d)
Set the WR bit. This will begin program
cycle.
cycle.
e)
CPU will stall for duration of the program
cycle.
cycle.
f)
The WR bit is cleared by the hardware
when program cycle ends.
when program cycle ends.
6.
Repeat steps 1 through 5 as needed to program
desired amount of program Flash memory.
desired amount of program Flash memory.
7.6.2
ERASING A ROW OF PROGRAM
MEMORY
MEMORY
Example 7-1 shows a code sequence that can be used
to erase a row (32 instructions) of program memory.
to erase a row (32 instructions) of program memory.
EXAMPLE 7-1:
ERASING A ROW OF PROGRAM MEMORY
; Setup NVMCON for erase operation, multi word write
; program memory selected, and writes enabled
MOV
#0x4041,W0
;
MOV
W0
,
NVMCON
; Init NVMCON SFR
; Init pointer to row to be ERASED
MOV
#tblpage(PROG_ADDR),W0
;
MOV
W0
,
NVMADRU
; Initialize PM Page Boundary SFR
MOV
#tbloffset(PROG_ADDR),W0
; Initialize in-page EA<15:0> pointer
MOV
W0, NVMADR
; Initialize NVMADR SFR
DISI
#5
; Block all interrupts with priority <7
; for next 5 instructions
MOV
#0x55,W0
MOV
W0
,
NVMKEY
; Write the 0x55 key
MOV
#0xAA,W1
;
MOV
W1
,
NVMKEY
; Write the 0xAA key
BSET
NVMCON,#WR
; Start the erase sequence
NOP
; Insert two NOPs after the erase
NOP
; command is asserted