Datasheet

© 2007-2011 Microchip Technology Inc. DS70265E-page 57
dsPIC33FJ12MC201/202
5.0 FLASH PROGRAM MEMORY
The dsPIC33FJ12MC201/202 devices contain internal
Flash program memory for storing and executing
application code. The memory is readable, writable,
and erasable during normal operation over the entire
V
DD range.
Flash memory can be programmed in two ways:
• In-Circuit Serial Programming™ (ICSP™)
programming capability
• Run-Time Self-Programming (RTSP)
ICSP allows a dsPIC33FJ12MC201/202 device to be
serially programmed while in the end application circuit.
This is done with two lines for programming clock and
programming data (one of the alternate programming
pin pairs: PGECx/PGEDx), and three other lines for
power (V
DD), ground (VSS) and Master Clear (MCLR).
This allows users to manufacture boards with
unprogrammed devices, and then program the digital
signal controller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
RTSP is accomplished using TBLRD (table read) and
TBLWT (table write) instructions. With RTSP, the user
application can write program memory data either in
blocks or ‘rows’ of 64 instructions (192 bytes) or a sin-
gle program memory word, and erase program mem-
ory in blocks or ‘pages’ of 512 instructions (1536
bytes).
5.1 Table Instructions and Flash
Programming
Regardless of the method used, all programming of
Flash memory is done with the table-read and table-
write instructions. These allow direct read and write
access to the program memory space from the data
memory while the device is in normal operating mode.
The 24-bit target address in the program memory is
formed using bits <7:0> of the TBLPAG register and the
Effective Address (EA) from a W register specified in
the table instruction, as shown in Figure 5-1.
The TBLRDL and the TBLWTL instructions are used to
read or write to bits <15:0> of program memory.
TBLRDL and TBLWTL can access program memory in
both Word and Byte modes.
The TBLRDH and TBLWTH instructions are used to read
or write to bits <23:16> of program memory. TBLRDH
and TBLWTH can also access program memory in Word
or Byte mode.
FIGURE 5-1: ADDRESSING FOR TABLE REGISTERS
Note 1: This data sheet summarizes the features
of the dsPIC33FJ12MC201/202 family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 5. “Flash Pro-
gramming” (DS70191) of the
“dsPIC33F/PIC24H Family Reference
Manual”, which is available from the
Microchip website (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
0 Program Counter
24 bits
Program Counter
TBLPAG Reg
8 bits
Working Reg EA
16 bits
Byte
24-bit EA
0
1/0
Select
Using
Table Instruction
Using
User/Configuration
Space Select