PIC18LF4610T-I Datasheet, PDF (160/376 Pages) Microchip Technology – 28/40/44-Pin Flash Microcontrollers

PIC18F2X1X/4X1X
16.4 I²C Mode
The MSSP module in I²C mode fully implements all
master and slave functions (including general call
support) and provides interrupts on Start and Stop bits
in hardware to determine a free bus (multi-master
function). The MSSP module implements the standard
mode specifications, as well as 7-bit and 10-bit
addressing.
Two pins are used for data transfer:
• Serial clock (SCL) – RC3/SCK/SCL
• Serial data (SDA) – RC4/SDI/SDA
The user must configure these pins as inputs or outputs
through the TRISC<4:3> bits.
FIGURE 16-7:
MSSP BLOCK DIAGRAM
(I²C™ MODE)
Read
Internal
Data Bus
Write
RC3/SCK/SCL
RC4/SDI/
SDA
SSPBUF reg
Shift
Clock
SSPSR reg
MSb
LSb
Match Detect
Addr Match
SSPADD reg
Start and
Stop bit Detect
Set, Reset
S, P bits
(SSPSTAT reg)
16.4.1 REGISTERS
The MSSP module has six registers for I²C operation.
These are:
• MSSP Control Register 1 (SSPCON1)
• MSSP Control Register 2 (SSPCON2)
• MSSP Status Register (SSPSTAT)
• Serial Receive/Transmit Buffer Register
(SSPBUF)
• MSSP Shift Register (SSPSR) – Not directly
accessible
• MSSP Address Register (SSPADD)
SSPCON1, SSPCON2 and SSPSTAT are the control
and status registers in I²C mode operation. The
SSPCON1 and SSPCON2 registers are readable and
writable. The lower 6 bits of the SSPSTAT are read-only.
The upper two bits of the SSPSTAT are read/write.
SSPSR is the shift register used for shifting data in or
out. SSPBUF is the buffer register to which data bytes
are written to or read from.
SSPADD register holds the slave device address when
the SSP is configured in I²C Slave mode. When the
SSP is configured in Master mode, the lower seven bits
of SSPADD act as the Baud Rate Generator reload
value.
In receive operations, SSPSR and SSPBUF together
create a double-buffered receiver. When SSPSR
receives a complete byte, it is transferred to SSPBUF
and the SSPIF interrupt is set.
During transmission, the SSPBUF is not double-
buffered. A write to SSPBUF will write to both SSPBUF
and SSPSR.
DS39636D-page 162
© 2009 Microchip Technology Inc.