PIC17C75X
2
15.2.10 I C MASTER MODE RECEPTION
15.2.10.1 BF STATUS FLAG
Master mode reception is enabled by programming
the receive enable bit, RCEN (SSPCON2<3>).
In receive operation, BF is set when an address or
data byte is loaded into SSPBUF from SSPSR. It is
cleared when SSPBUF is read.
Note: The SSP Module must be in IDLE mode
before the RCE bit is set, or the RCEN bit
will be disreguarded.
15.2.10.2 SSPOV STATUS FLAG
In receive operation, SSPOV is set when 8 bits are
received into the SSPSR, and the BF flag is already
set from a previous reception.
The baud rate generator begins counting, and on
each rollover, the state of the SCL pin changes (high
to low/low to high), and data is shifted into the SSPSR.
After the falling edge of the eighth clock, the receive
enable flag is automatically cleared, the contents of
the SSPSR are loaded into the SSPBUF, the BF flag is
set, the SSPIF is set, and the baud rate generator is
suspended from counting, holding SCL low. The SSP
is now in IDLE state, awaiting the next command.
When the buffer is read by the CPU, the BF flag is
automatically cleared. The user can then send an
acknowledge bit at the end of reception, by setting the
15.2.10.3 WCOL STATUS FLAG
If the user writes the SSPBUF when a receive is
already in progress (i.e. SSPSR is still shifting in a
data byte), then WCOL is set and the contents of the
buffer are unchanged (the write doesn’t occur).
acknowledge
sequence
enable
bit,
ACKEN
(SSPCON2<4>).
DS30264A-page 152
Preliminary
1997 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
