PIC18LF4455-I/PT Microchip Technology, PIC18LF4455-I/PT Datasheet - Page 89

• Manufacturer Part Number: PIC18LF4455-I/PT
• Description: IC PIC MCU FLASH 12KX16 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF4455-I/PT

• Core Size: 8-Bit
• Program Memory Size: 24KB (12K x 16)
• Core Processor: PIC
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Controller Family/series: PIC18
• No. Of I/o's: 36
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 2048Byte
• Cpu Speed: 48MHz
• No. Of Timers: 4
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, I2C, EAUSART
• Maximum Clock Frequency: 48 MHz
• Number Of Programmable I/os: 35
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136, DM163025
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 13 Channel
• Package: 44TQFP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 48 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

6.5
The minimum programming block is 16 words or
32 bytes. Word or byte programming is not supported.
Table writes are used internally to load the holding
registers needed to program the Flash memory. There
are 32 holding registers used by the table writes for
programming.
Since the Table Latch (TABLAT) is only a single byte, the
TBLWT instruction may need to be executed 32 times for
each programming operation. All of the table write oper-
ations will essentially be short writes because only the
holding registers are written. At the end of updating the
32 holding registers, the EECON1 register must be
written to in order to start the programming operation
with a long write.
FIGURE 6-5:
6.5.1
The sequence of events for programming an internal
program memory location should be:
1.
2.
3.
4.
5.
6.
7.
© 2009 Microchip Technology Inc.
TBLPTR = xxxx00
Read 64 bytes into RAM.
Update data values in RAM as necessary.
Load Table Pointer register with address being
erased.
Execute the Row Erase procedure.
Load Table Pointer register with address of first
byte being written.
Write 32 bytes into the holding registers with
auto-increment.
Set the EECON1 register for the write operation:
• set EEPGD bit to point to program memory;
• clear the CFGS bit to access program memory;
• set WREN to enable byte writes.
Writing to Flash Program Memory
FLASH PROGRAM MEMORY WRITE
SEQUENCE
Holding Register
TABLE WRITES TO FLASH PROGRAM MEMORY
8
TBLPTR = xxxx01
Holding Register
PIC18F2455/2550/4455/4550
8
Program Memory
TBLPTR = xxxx02
Write Register
TABLAT
The long write is necessary for programming the
internal Flash. Instruction execution is halted while in a
long write cycle. The long write will be terminated by
the internal programming timer.
The EEPROM on-chip timer controls the write time.
The write/erase voltages are generated by an on-chip
charge pump, rated to operate over the voltage range
of the device.
8.
9.
10. Write 0AAh to EECON2.
11. Set the WR bit. This will begin the write cycle.
12. The CPU will stall for duration of the write (about
13. Re-enable interrupts.
14. Repeat steps 6 through 14 once more to write
15. Verify the memory (table read).
This procedure will require about 8 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 6-3.
Note:
Note:
Holding Register
Disable interrupts.
Write 55h to EECON2.
2 ms using internal timer).
64 bytes.
8
The default value of the holding registers on
device Resets and after write operations is
FFh. A write of FFh to a holding register
does not modify that byte. This means that
individual bytes of program memory may be
modified, provided that the change does not
attempt to change any bit from a ‘0’ to a ‘1’.
When modifying individual bytes, it is not
necessary to load all 32 holding registers
before executing a write operation.
Before setting the WR bit, the Table
Pointer address needs to be within the
intended address range of the 32 bytes in
the holding register.
TBLPTR = xxxx1F
Holding Register
DS39632E-page 87
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