Datasheet

 2010-2013 Microchip Technology Inc. DS39881E-page 47
PIC24FJ64GA004 FAMILY
5.0 FLASH PROGRAM MEMORY
The PIC24FJ64GA004 family of devices contains inter-
nal Flash program memory for storing and executing
application code. The memory is readable, writable and
erasable when operating with V
DD over 2.25V.
Flash memory can be programmed in three ways:
• In-Circuit Serial Programming™ (ICSP™)
• Run-Time Self-Programming (RTSP)
• Enhanced In-Circuit Serial Programming
(Enhanced ICSP)
ICSP allows a PIC24FJ64GA004 family device to be
serially programmed while in the end application circuit.
This is simply done with two lines for the programming
clock and programming data (which are named PGCx
and PGDx, respectively), and three other lines for
power (V
DD), ground (VSS) and Master Clear (MCLR).
This allows customers to manufacture boards with
unprogrammed devices and then program the micro-
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
may write program memory data in blocks of 64 instruc-
tions (192 bytes) at a time and erase program memory
in blocks of 512 instructions (1536 bytes) at a time.
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 the TBLPAG<7:0> bits 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: This data sheet summarizes the features of
this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. For more information, refer to the
“PIC24F Family Reference Manual”,
“Program Memory” (DS39715).
0
Program Counter
24 Bits
Program
TBLPAG Reg
8 Bits
Working Reg EA
16 Bits
Using
Byte
24-Bit EA
0
1/0
Select
Table
Instruction
Counter
Using
User/Configuration
Space Select