PIC18F2423-I/ML Microchip Technology, PIC18F2423-I/ML Datasheet - Page 13

• Manufacturer Part Number: PIC18F2423-I/ML
• Description: 16KB, Flash, 768bytes-RAM, 25I/O, 8-bit Family,nanoWatt 28 QFN 6x6mm TUBE
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2423-I/ML

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28QFN4 - SOCKET TRANS ICE 28QFN W/CABLEAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.2
Programming code memory is accomplished by first
loading data into the write buffer and then initiating a
programming sequence. The write and erase buffer
sizes, shown in Table 3-4, can be mapped to any
location of the same size beginning at 000000h. The
actual memory write sequence takes the contents of
this buffer and programs the proper amount of code
memory that contains the Table Pointer.
The programming duration is externally timed and is
controlled by PGC. After a Start Programming
command is issued (4-bit command, ‘1111’), a NOP is
issued, where the 4th PGC is held high for the duration
of the programming time, P9.
After PGC is brought low, the programming sequence
is terminated. PGC must be held low for the time
specified by parameter P10 to allow high-voltage
discharge of the memory array.
TABLE 3-5:
© 2005 Microchip Technology Inc.
Step 1: Direct access to code memory and enable writes.
Step 2: Load write buffer.
Step 3: Repeat for all but the last two bytes.
Step 4: Load write buffer for last two bytes.
To continue writing data, repeat steps 2 through 4, where the Address Pointer is incremented by 2 at each iteration of the loop.
Command
0000
0000
0000
0000
0000
0000
0000
0000
1101
1111
0000
4-Bit
Code Memory Programming
8E A6
9C A6
0E <Addr[21:16]>
6E F8
0E <Addr[15:8]>
6E F7
0E <Addr[7:0]>
6E F6
<MSB><LSB>
<MSB><LSB>
00 00
WRITE CODE MEMORY CODE SEQUENCE
Data Payload
BSF
BCF
MOVLW <Addr[21:16]>
MOVWF TBLPTRU
MOVLW <Addr[15:8]>
MOVWF TBLPTRH
MOVLW <Addr[7:0]>
MOVWF TBLPTRL
Write 2 bytes and post-increment address by 2.
Write 2 bytes and start programming.
NOP - hold PGC high for time P9 and low for time P10.
PIC18F2423/2523/4423/4523
EECON1, EEPGD
EECON1, CFGS
The code sequence to program a PIC18F2423/2523/
4423/4523 device is shown in Table 3-5. The flowchart,
shown in Figure 3-4, depicts the logic necessary to
completely
device. The timing diagram that details the Start
Programming command and parameters P9 and P10 is
shown in Figure 3-5.
TABLE 3-4:
Note:
PIC18F2423
PIC18F2523
PIC18F4423
PIC18F4523
Devices
Core Instruction
The TBLPTR register must point to the
same region when initiating the program-
ming sequence as it did when the write
buffers were loaded.
write
WRITE AND ERASE BUFFER
SIZES
Write Buffer
a
Size (bytes)
PIC18F2423/2523/4423/4523
32
DS39759A-page 13
Erase Buffer
Size (bytes)
64