PIC24H Microchip Technology, PIC24H Datasheet - Page 48

• Manufacturer Part Number: PIC24H
• Description: Flash Programming Specification
• Manufacturer: Microchip Technology

dsPIC33F/PIC24H PROGRAMMING SPECIFICATION
FIGURE 4-2:
4.2
The programming executive command set is shown in
Table 4-1. This table contains the opcode, mnemonic,
length, time out and description for each command.
Functional details on each command are provided in
the command descriptions (Section 4.2.4 “Command
Descriptions”).
4.2.1
All programming executive commands have a general
format consisting of a 16-bit header and any required
data for the command (see Figure 4-3). The 16-bit
header consists of a 4-bit opcode field, which is used to
identify the command, followed by a 12-bit command
length field.
FIGURE 4-3:
The command opcode must match one of those in the
command set. Any command that is received which
does not match the list in Table 4-1 will return a “NACK”
response (see Section 5.3.1.1 “Opcode Field”).
The command length is represented in 16-bit words
since the SPI operates in 16-bit mode. The program-
ming executive uses the command length field to
determine the number of words to read from the SPI
port. If the value of this field is incorrect, the command
will not be properly received by the programming
executive.
DS70152D-page 48
15
Opcode
Command Data First Word (if required)
Command Data Last Word (if required)
PGC
PGD
Programming Executive
Commands
12
COMMAND FORMAT
11
MSB X X X LSB
1
Last Command Word
PGC = Input
PGD = Input
2
Host Transmits
PROGRAMMING EXECUTIVE – PROGRAMMER COMMUNICATION PROTOCOL
COMMAND FORMAT
15 16
•
•
Length
P8
Programming Executive
PGC = Input (Idle)
PGD = Output
P9a
Processes Command
1
Preliminary
0
P9b
0
23 µs
4.2.2
When 24-bit instruction words are transferred across
the 16-bit SPI interface, they are packed to conserve
space using the format shown in Figure 4-4. This
format minimizes traffic over the SPI and provides the
programming executive with data that is properly
aligned for performing table write operations.
FIGURE 4-4:
4.2.3
The
unsupported commands. Additionally, due to the
memory constraints of the programming executive, no
checking is performed on the data contained in the
programmer command. It is the responsibility of the
programmer to command the programming executive
with valid command arguments or the programming
operation may fail. Additional information on error
handling is provided in Section 5.3.1.3 “QE_Code
Field”.
LSWx: Least Significant 16 bits of instruction word
MSBx: Most Significant Byte of instruction word
Note:
15
programming
1
MSB X X X LSB
MSB2
PACKED DATA FORMAT
When the number of instruction words
transferred is odd, MSB2 is zero and
LSW2 can not be transmitted.
PROGRAMMING EXECUTIVE
ERROR HANDLING
2
Host Clocks Out Response
15 16
PGC = Input
PGD = Output
PACKED INSTRUCTION
WORD FORMAT
executive
© 2007 Microchip Technology Inc.
LSW1
LSW2
8ns
8
7
1
MSB X X X LSB
2
will
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MSB1
15 16
“NACK”
0
all