PIC18F4585-I/PT Microchip Technology, PIC18F4585-I/PT Datasheet - Page 67

• Manufacturer Part Number: PIC18F4585-I/PT
• Description: IC MCU FLASH 24KX16 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F4585-I/PT

• Core Size: 8-Bit
• Program Memory Size: 48KB (24K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.25K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 11x10b
• 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: 1024Byte
• Ram Memory Size: 3.25KB
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPI3-DB18F4680 - BOARD DAUGHTER ICEPIC3AC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCUAC164020 - MODULE SKT PROMATEII 44TQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

5.2
5.2.1
The microcontroller clock input, whether from an inter-
nal or external source, is internally divided by four to
generate four non-overlapping quadrature clocks (Q1,
Q2, Q3 and Q4). Internally, the Program Counter (PC)
is incremented on every Q1; the instruction is fetched
from the program memory and latched into the Instruc-
tion Register (IR) 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.
FIGURE 5-3:
EXAMPLE 5-3:
© 2007 Microchip Technology Inc.
1. MOVLW 55h
2. MOVWF PORTB
3. BRA
4. BSF
5. Instruction @ address SUB_1
Note:
OSC2/CLKO
(RC mode)
PIC18 Instruction Cycle
SUB_1
CLOCKING SCHEME
PORTA, BIT3 (Forced NOP)
OSC1
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.
PC
Q1
Q2
Q3
Q4
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
PIC18F2585/2680/4585/4680
T
CY
Q1
1
Preliminary
Fetch INST (PC + 2)
Execute INST (PC)
Q2
Execute 2
Fetch 3
PC + 2
T
CY
Q3
2
5.2.2
An “Instruction Cycle” consists of four Q cycles: Q1
through Q4. The instruction fetch and execute are pipe-
lined 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 (Example 5-3).
A fetch cycle begins with the program counter
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
T
CY
INSTRUCTION FLOW/PIPELINING
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
Q4
DS39625C-page 65
T
CY
Internal
Phase
Clock
5