PIC18F24K22-I/SO Microchip Technology, PIC18F24K22-I/SO Datasheet - Page 74

• Manufacturer Part Number: PIC18F24K22-I/SO
• Description: IC PIC MCU 16KB FLASH 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F24K22-I/SO

• Core Size: 8-Bit
• Program Memory Size: 16KB (8K x 16)
• Core Processor: PIC
• Speed: 64MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 24
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 19x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Controller Family/series: PIC18
• No. Of I/o's: 25
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 768Byte
• Cpu Speed: 64MHz
• No. Of Timers: 7
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC18(L)F2X/4XK22
5.2
5.2.1
The microcontroller clock input, whether from an
internal or external source, is internally divided by four
to generate four non-overlapping quadrature clocks
(Q1, Q2, Q3 and Q4). Internally, the program counter is
incremented on every Q1; the instruction is fetched
from the program memory and latched into the
instruction register during Q4. The instruction is
decoded and executed during the following Q1 through
Q4. The clocks and instruction execution flow are
shown in
FIGURE 5-3:
EXAMPLE 5-3:
DS41412D-page 74
1. MOVLW 55h
2. MOVWF PORTB
3. BRA
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/CLKOUT
(RC mode)
PIC18 Instruction Cycle
Figure
SUB_1
CLOCKING SCHEME
PORTA, BIT3 (Forced NOP)
OSC1
Q1
Q2
Q3
Q4
PC
5-3.
CLOCK/INSTRUCTION CYCLE
INSTRUCTION PIPELINE FLOW
Q1
Execute INST (PC – 2)
Fetch INST (PC)
Q2
Fetch 1
T
PC
CY
0
Q3
Q4
Execute 1
Fetch 2
T
CY
1
Q1
Preliminary
Fetch INST (PC + 2)
Execute INST (PC)
Execute 2
Q2
Fetch 3
PC + 2
T
CY
2
5.2.2
An “Instruction Cycle” consists of four Q cycles: Q1
through Q4. The instruction fetch and execute are
pipelined in such a manner that a fetch takes one
instruction cycle, while the 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
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).
Q3
Execute 3
Q4
Fetch 4
T
CY
INSTRUCTION FLOW/PIPELINING
3
Q1
Execute INST (PC + 2)
Fetch INST (PC + 4)
Fetch SUB_1 Execute SUB_1
Flush (NOP)
Q2
T
 2010 Microchip Technology Inc.
PC + 4
(Example
CY
4
Q3
5-3).
Q4
T
CY
Internal
Phase
Clock
5