DSPIC33FJ64GP306 Microchip Technology Inc., DSPIC33FJ64GP306 Datasheet - Page 70

• Manufacturer Part Number: DSPIC33FJ64GP306
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

dsPIC33FJXXXGPX06/X08/X10
4.2
The dsPIC33FJXXXGPX06/X08/X10 Flash program
memory array is organized into rows of 64 instructions
or 192 bytes. RTSP allows the user 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. Table 24-12, DC Characteristics: Program
Memory 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, respec-
tively.
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 in sequential order. 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 set-
ting 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
written.
programming each row.
DS70286A-page 68
RTSP Operation
A
programming
cycle
is
required
for
4.3
There are two SFRs used to read and write the
program Flash memory:
• NVMCON: Flash Memory Control Register
• NVMKEY: Non-Volatile Memory Key Register
The NVMCON register (Register 4-1) controls which
blocks are to be erased, which memory type is to be
programmed and the start of the programming cycle.
NVMKEY (Register 4-2) is a write-only register that is
used for write protection. To start a programming or
erase sequence, the user must consecutively write 55h
and AAh to the NVMKEY register. Refer to Section 4.4
“Programming Operations” for further details.
4.4
A complete programming sequence is necessary for
programming or erasing the internal Flash in RTSP
mode. A programming operation is nominally 4 ms 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.
Control Registers
Programming Operations
© 2007 Microchip Technology Inc.