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dsPIC33FJ32GP202/204 and dsPIC33FJ16GP304
DS70290J-page 56
© 2007-2011 Microchip Technology Inc.
5.2
RTSP Operation
The dsPIC33FJ32GP202/204 and
dsPIC33FJ16GP304 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. 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. A programming cycle is required for
programming each row.
5.3
Programming Operations
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 
). 
EQUATION 5-1:
PROGRAMMING TIME
For example, if the device is operating at +125
° C, the
FRC accuracy will be ±5%. If the TUN<5:0> bits (see
) are set to ‘b111111, the minimum row
write time is equal to 
.
EQUATION 5-2:
MINIMUM ROW WRITE 
TIME
The maximum row write time is equal to 
EQUATION 5-3:
MAXIMUM ROW WRITE 
TIME
Setting the WR bit (NVMCON<15>) starts the
operation, and the WR bit is automatically cleared
when the operation is finished.
5.4
Flash Memory Resources
Many useful resources are provided on the main prod-
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this 
, contains the latest updates
and additional information.
5.4.1
KEY RESOURCES
• Section 5. “Flash Programming” (DS70191)
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related dsPIC33F/PIC24H Family Reference 
Manuals Sections
• Development Tools
5.5
Control Registers
The two SFRs that are used to read and write the
program Flash memory are: 
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 
T
7.37 MHz
FRC Accuracy
(
)%
FRC Tuning
(
)%
×
×
----------------------------------------------------------------------------------------------------------------------------
T
RW
11064 Cycles
7.37 MHz
1 0.05
+
(
)
1 0.00375
(
)
×
×
------------------------------------------------------------------------------------------------ 1.435ms
=
=
Note:
In the event you are not able to access
the product page using the link above,
enter this URL in your browser:
T
RW
11064 Cycles
7.37 MHz
1 0.05
(
)
1 0.00375
(
)
×
×
------------------------------------------------------------------------------------------------ 1.586ms
=
=