PIC16F877T-20/PT Microchip Technology, PIC16F877T-20/PT Datasheet - Page 285

• Manufacturer Part Number: PIC16F877T-20/PT
• Description: IC MCU FLASH 8KX14 EE 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877T-20/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Size: 14KB (8K x 14)
• 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: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

17.3
17.3.1
1997 Microchip Technology Inc.
Operation
SPI Mode
The SPI mode allows 8-bits of data to be synchronously transmitted and received simulta-
neously. All four modes of SPI are supported. To accomplish communication, typically three pins
are used:
• Serial Data Out (SDO)
• Serial Data In (SDI)
• Serial Clock (SCK)
Additionally a fourth pin may be used when in a slave mode of operation:
• Slave Select (SS)
When initializing the SPI, several options need to be specified. This is done by programming the
appropriate control bits in the SSPCON1 register (SSPCON1<5:0>) and SSPSTAT<7:6>. These
control bits allow the following to be specified:
• Master Mode (SCK is the clock output)
• Slave Mode (SCK is the clock input)
• Clock Polarity (Idle state of SCK)
• Data input sample phase (middle or end of data output time)
• Clock edge (output data on rising/falling edge of SCK)
• Clock Rate (Master mode only)
• Slave Select Mode (Slave mode only)
Figure 17-4
Figure 17-4:
shows the block diagram of the SSP module, when in SPI mode.
SSP Block Diagram (SPI Mode)
SDO
SCK
SDI
SS
Preliminary
Read
SS Control
Select
SMP:CKE
Edge
Enable
bit0
Select
Edge
SSPBUF reg
TRIS bit
Data to TX/RX in SSPSR
2
SSPM3:SSPM0
SSPSR reg
Clock Select
Section 17. MSSP
4
2
Write
Prescaler
4, 16, 64
clock
shift
TMR2 output
data bus
Internal
2
T
OSC
DS31017A-page 17-9
17