Datasheet
PIC16F87/88
DS30487D-page 90 2002-2013 Microchip Technology Inc.
FIGURE 10-1: SSP BLOCK DIAGRAM
(SPI MODE)
To enable the serial port, SSP Enable bit, SSPEN
(SSPCON<5>), must be set. To reset or reconfigure
SPI mode, clear bit SSPEN, reinitialize the SSPCON
register and then set bit SSPEN. This configures the
SDI, SDO, SCK and SS
pins as serial port pins. For the
pins to behave as the serial port function, they must
have their data direction bits (in the TRISB register)
appropriately programmed. That is:
• SDI must have TRISB<1> set
• SDO must have TRISB<2> cleared
• SCK (Master mode) must have TRISB<4>
cleared
• SCK (Slave mode) must have TRISB<4> set
•SS
must have TRISB<5> set
TABLE 10-1: REGISTERS ASSOCIATED WITH SPI OPERATION
Read Write
Internal
Data Bus
RB1/SDI/SDA
RB2/SDO/RX/DT
RB5/SS
/
RB4/SCK/
SSPSR reg
SSPBUF reg
SSPM3:SSPM0
bit0
Shift
Clock
SS
Control
Enable
Edge
Select
Clock Select
TMR2 Output
T
CY
Prescaler
4, 16, 64
TRISB<4>
2
Edge
Select
2
4
SCL
TX/CK
Note 1: When the SPI is in Slave mode with SS pin
control enabled (SSPCON<3:0> = 0100),
the SPI module will reset if the SS
pin is
set to V
DD.
2: If the SPI is used in Slave mode with
CKE = 1, then the SS
pin control must be
enabled.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
POR, BOR
Value on
all other
Resets
0Bh,8Bh
10Bh,18Bh
INTCON GIE PEIE
TMR0IE INT0IE RBIE TMR0IF INT0IF RBIF 0000 000x 0000 000u
0Ch PIR1
— ADIF
(1)
RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF -000 0000 -000 0000
8Ch PIE1
— ADIE
(1)
RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE -000 0000 -000 0000
86h TRISB PORTB Data Direction Register 1111 1111 1111 1111
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000
94h SSPSTAT SMP CKE
D/A P S R/W UA BF 0000 0000 0000 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the SSP in SPI mode.
Note 1: This bit is only implemented on the PIC16F88. The bit will read ‘0’ on the PIC16F87.