PIC18F2431-I/SO Microchip Technology, PIC18F2431-I/SO Datasheet - Page 65

• Manufacturer Part Number: PIC18F2431-I/SO
• Description: IC PIC MCU FLASH 8KX16 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2431-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 16KB (8K x 16)
• Package / Case: 28-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, Power Control PWM, QEI, POR, PWM, WDT
• Number Of I /o: 24
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: EUSART/I2C/SPI/SSP
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 24
• 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, DM183021, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Package: 28SOIC W
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MILI3-DB18F4431 - BOARD DAUGHTER ICEPIC3
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

6.1.4.2
A better method of storing data in program memory
allows two bytes of data to be stored in each instruction
location. Look-up table data may be stored, two bytes
per program word, by using table reads and writes.
The Table Pointer register (TBLPTR) specifies the byte
address and the Table Latch register (TABLAT) con-
tains the data that is read from or written to program
memory. Data is transferred to or from program
memory, one byte at a time.
Table read and table write operations are discussed
further in
Writes”.
FIGURE 6-4:
6.3
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute take another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO),
then two cycles are required to complete the instruction
(Example
EXAMPLE 6-3:
 2010 Microchip Technology Inc.
1. MOVLW 55h
2. MOVWF PORTB
3. BRA SUB_1
4. BSF
5. Instruction @ address SUB_1
All instructions are single cycle, except for any program branches. These take two cycles since the fetch instruction
is “flushed” from the pipeline, while the new instruction is being fetched and then executed.
OSC2/CLKO
(RC mode)
Instruction Flow/Pipelining
6-3).
Section 8.1 “Table Reads and Table
PORTA, BIT3 (Forced NOP)
Table Reads and Table Writes
OSC1
Q4
PC
Q2
Q3
Q1
Q1
CLOCK/INSTRUCTION CYCLE
INSTRUCTION PIPELINE FLOW
Execute INST (PC – 2)
Fetch INST (PC)
Q2
Fetch 1
T
PC
CY
Q3
0
Q4
Execute 1
Fetch 2
PIC18F2331/2431/4331/4431
T
CY
Q1
1
Fetch INST (PC + 2)
Execute INST (PC)
Q2
Execute 2
Fetch 3
PC + 2
T
CY
Q3
2
6.2
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks, namely Q1, Q2, Q3 and Q4. Internally, the
Program Counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the Instruction Register (IR) in Q4. The
instruction is decoded and executed during the
following Q1 through Q4. The clocks and instruction
execution flow are shown in
A fetch cycle begins with the Program Counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the “Instruction Register” (IR) in cycle, Q1. This
instruction is then decoded and executed during the
Q2, Q3 and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
Q4
Execute 3
Fetch 4
Clocking Scheme/Instruction
Cycle
T
CY
3
Q1
Execute INST (PC + 2)
Fetch INST (PC + 4)
Fetch SUB_1 Execute SUB_1
Flush (NOP)
Q2
PC + 4
T
CY
Q3
4
Figure
Q4
6-4.
DS39616D-page 65
T
CY
Internal
Phase
Clock
5