Microchip Technology DM164130-7 Data Sheet
2010-2012 Microchip Technology Inc.
DS41414D-page 247
PIC16(L)F1946/47
FIGURE 24-4:
SPI MASTER AND MULTIPLE SLAVE CONNECTION
24.2.1 SPI MODE REGISTERS
The MSSPx module has five registers for SPI mode
operation. These are:
• MSSPx STATUS register (SSPxSTAT)
• MSSPx Control Register 1 (SSPxCON1)
• MSSPx Control Register 3 (SSPxCON3)
• MSSPx Data Buffer register (SSPxBUF)
• MSSPx Address register (SSPxADD)
• MSSPx Shift register (SSPxSR)
operation. These are:
• MSSPx STATUS register (SSPxSTAT)
• MSSPx Control Register 1 (SSPxCON1)
• MSSPx Control Register 3 (SSPxCON3)
• MSSPx Data Buffer register (SSPxBUF)
• MSSPx Address register (SSPxADD)
• MSSPx Shift register (SSPxSR)
(Not directly accessible)
SSPxCON1 and SSPxSTAT are the control and
STATUS registers in SPI mode operation. The
SSPxCON1 register is readable and writable. The
lower 6 bits of the SSPxSTAT are read-only. The upper
two bits of the SSPxSTAT are read/write.
In SPI master mode, SSPxADD can be loaded with a
value used in the Baud Rate Generator. More informa-
tion on the Baud Rate Generator is available in
STATUS registers in SPI mode operation. The
SSPxCON1 register is readable and writable. The
lower 6 bits of the SSPxSTAT are read-only. The upper
two bits of the SSPxSTAT are read/write.
In SPI master mode, SSPxADD can be loaded with a
value used in the Baud Rate Generator. More informa-
tion on the Baud Rate Generator is available in
SSPxSR is the shift register used for shifting data in
and out. SSPxBUF provides indirect access to the
SSPxSR register. SSPxBUF is the buffer register to
which data bytes are written, and from which data
bytes are read.
In receive operations, SSPxSR and SSPxBUF
together create a buffered receiver. When SSPxSR
receives a complete byte, it is transferred to SSPxBUF
and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not buffered. A
write to SSPxBUF will write to both SSPxBUF and
SSPxSR.
and out. SSPxBUF provides indirect access to the
SSPxSR register. SSPxBUF is the buffer register to
which data bytes are written, and from which data
bytes are read.
In receive operations, SSPxSR and SSPxBUF
together create a buffered receiver. When SSPxSR
receives a complete byte, it is transferred to SSPxBUF
and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not buffered. A
write to SSPxBUF will write to both SSPxBUF and
SSPxSR.
SPI Master
SCKx
SDOx
SDIx
General I/O
General I/O
General I/O
General I/O
General I/O
SCKx
SDIx
SDOx
SSx
SDIx
SDOx
SSx
SPI Slave
#1
SCKx
SDIx
SDOx
SSx
SDIx
SDOx
SSx
SPI Slave
#2
SCKx
SDIx
SDOx
SSx
SDIx
SDOx
SSx
SPI Slave
#3