PIC16F877-20/P Microchip Technology, PIC16F877-20/P Datasheet - Page 71

• Manufacturer Part Number: PIC16F877-20/P
• Description: IC MCU FLASH 8KX14 EE 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877-20/P

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Section 4. Architecture
Instruction Pipeline:
The instruction pipeline is a two-stage pipeline which overlaps the fetch and execution of instruc-
tions. The fetch of the instruction takes one T
, while the execution takes another T
. However,
CY
CY
due to the overlap of the fetch of current instruction and execution of previous instruction, an
instruction is fetched and another instruction is executed every single T
.
CY
Single Cycle Instructions:
With the Program Memory bus being 14-bits wide, the entire instruction is fetched in a single
machine cycle (T
). The instruction contains all the information required and is executed in a
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single cycle. There may be a one cycle delay in execution if the result of the instruction modified
the contents of the Program Counter. This requires the pipeline to be flushed and a new instruc-
tion to be fetched.
Reduced Instruction Set:
When an instruction set is well designed and highly orthogonal (symmetric), fewer instructions
are required to perform all needed tasks. With fewer instructions, the whole set can be more rap-
idly learned.
Register File Architecture:
The register files/data memory can be directly or indirectly addressed. All special function regis-
ters, including the program counter, are mapped in the data memory.
Orthogonal (Symmetric) Instructions:
Orthogonal instructions make it possible to carry out any operation on any register using any
addressing mode. This symmetrical nature and lack of “special instructions” make programming
simple yet efficient. In addition, the learning curve is reduced significantly. The mid-range instruc-
tion set uses only two non-register oriented instructions, which are used for two of the cores fea-
tures. One is the SLEEP instruction which places the device into the lowest power use mode. The
other is the CLRWDT instruction which verifies the chip is operating properly by preventing the
on-chip Watchdog Timer (WDT) from overflowing and resetting the device.
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1997 Microchip Technology Inc.
DS31004A-page 4-3