Microchip Technology MA330024 Data Sheet

DS70000591F-page 110

 2009-2014 Microchip Technology Inc.

The dsPIC33FJ32GS406/606/608/610 and
dsPIC33FJ64GS406/606/608/610 Flash program
memory array is organized into rows of 64 instructions or
192 bytes. RTSP allows the user application to erase a
page of memory, which consists of eight rows
(512 instructions) at a time, and to program one row or
one word at a time. 

 shows typical erase and

programming times. The 8-row erase pages and single
row write rows are edge-aligned from the beginning of
program memory, on boundaries of 1536 bytes and
192 bytes, respectively.

The program memory implements holding buffers that
can contain 64 instructions of programming data. Prior
to the actual programming operation, the write data
must be loaded into the buffers sequentially. The
instruction words loaded must always be from a group
of 64 boundary.

The basic sequence for RTSP programming is to set up
a Table Pointer, then do a series of TBLWT instructions
to load the buffers. Programming is performed by
setting the control bits in the NVMCON register. A total
of 64 TBLWTL  and TBLWTH  instructions are required
to load the instructions.

All of the Table Write operations are single-word writes
(two instruction cycles) because only the buffers are writ-
ten. A programming cycle is required for programming
each row.

A complete programming sequence is necessary for
programming or erasing the internal Flash in RTSP
mode. The processor stalls (waits) until the
programming operation is finished. 

The programming time depends on the FRC accuracy
(see 

) and the value of the FRC Oscillator

Tuning register (see 

). Use the following

formula to calculate the minimum and maximum values
for the Row Write Time, Page Erase Time and Word
Write Cycle Time parameters (see 

).

For example, if the device is operating at +125°C, the
FRC accuracy will be ±2%. If the TUN<5:0> bits (see

) are set to ‘b000000, the minimum row

write time is equal to 

The maximum row write time is equal to 

Setting the WR bit (NVMCON<15>) starts the
operation and the WR bit is automatically cleared
when the operation is finished.

Two SFRs are used to read and write the program
Flash memory: NVMCON and NVMKEY.

The NVMCON register (

) controls which

blocks are to be erased, which memory type is to be
programmed and the start of the programming cycle.

NVMKEY is a write-only register that is used for write
protection. To start a programming or erase sequence,
the user application must consecutively write 0x55 and
0xAA to the NVMKEY register. Refer to 

 for further details.

7.37 MHz



%



%





--------------------------------------------------------------------------------------------------------------------------

 (1 + 0.02)  (1 – 0.000938)

 (1 – 0.02)  (1 – 0.000938)