dspic33fj128mc204 Microchip Technology Inc., dspic33fj128mc204 Datasheet - Page 75

• Manufacturer Part Number: dspic33fj128mc204
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

5.2
The dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/
X04, and dsPIC33FJ128MCX02/X04 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. Table 31-12 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
written.
programming each row.
© 2009 Microchip Technology Inc.
RTSP Operation
A
programming
cycle
is
required
Preliminary
for
5.3
A complete programming sequence is necessary for
programming or erasing the internal Flash in RTSP
mode.
programming operation is finished.
The programming time depends on the FRC accuracy
(see Table 31-19) and the value of the FRC Oscillator
Tuning register (see Register 9-4). 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 Table 31-12).
EQUATION 5-1:
For example, if the device is operating at +125°C,
the FRC accuracy will be ±5%. If the TUN<5:0> bits
(see Register 9-4) are set to ‘b111111, the
Minimum Row Write Time is:
and, the Maximum Row Write Time is:
Setting the WR bit (NVMCON<15>) starts the opera-
tion, and the WR bit is automatically cleared when the
operation is finished.
5.4
Two SFRs are used to read and write the program
Flash memory: NVMCON and NVMKEY.
The NVMCON register (Register 5-1) controls which
blocks are to be erased, which memory type is to be
programmed and the start of the programming cycle.
NVMKEY (Register 5-2) is a write-only register that is
used for write protection. To start a programming or
erase sequence, the user application must consecu-
tively write 0x55 and 0xAA to the NVMKEY register.
Refer to Section 5.3 “Programming Operations” for
further details.
T
T
RW
RW
------------------------------------------------------------------------------------------------------------------------- -
7.37 MHz
=
=
--------------------------------------------------------------------------------------------- - 1.586ms
7.37 MHz
--------------------------------------------------------------------------------------------- - 1.435ms
7.37 MHz
The
Programming Operations
Control Registers
×
processor
(
FRC Accuracy
×
×
(
(
11064 Cycles
11064 Cycles
1 0.05
1
–
+
PROGRAMMING TIME
0.05
T
stalls
)
)
×
×
)%
(
(
1 0.00375
1 0.00375
×
–
–
(
(waits)
FRC Tuning
DS70291C-page 73
)
)
=
=
until
)%
the