PIC16F877-20/P Microchip Technology, PIC16F877-20/P Datasheet - Page 262

• 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

PICmicro MID-RANGE MCU FAMILY
16.3.6
DS31016A-page 16-12
SCK
(CKP = 0)
SCK
(CKP = 1)
SS
SSPIF
SDO
SDI
Slave Select Mode
The SS pin allows a synchronous slave mode. The SPI must be in slave mode
(SSPCON<3:0> = 04h) and the TRIS bit must be set the for the synchronous slave mode to be
enabled. When the SS pin is low, transmission and reception are enabled and the SDO pin is
driven. When the SS pin goes high, the SDO pin is no longer driven, even if in the middle of a
transmitted byte, and becomes a floating output. If the SS pin is taken low without resetting SPI
mode, the transmission will continue from the point at which it was taken high. To clear the bit
counter the Basic SSP module must be disabled and then re-enabled. External pull-up/pull-down
resistors may be desirable, depending on the application.
To emulate two-wire communication, the SDO pin can be connected to the SDI pin. When the
SPI needs to operate as a receiver the SDO pin can be configured as an input. This disables
transmissions from the SDO. The SDI can always be left as an input (SDI function) since it cannot
create a bus conflict.
Figure 16-5: SPI Mode Waveform (Slave Mode with ss Control)
bit7
bit7
bit6
bit5
bit4
bit3
bit2
Next Q4 Cycle
after Q2
1997 Microchip Technology Inc.
bit1
bit0
bit0