PIC16F87X
2
9.2.12 I C MASTER MODE RECEPTION
Master mode reception is enabled by programming the
receive enable bit, RCEN (SSPCON2<3>).
Note: The SSP module must be in an IDLE
STATE before the RCEN bit is set or the
RCEN bit will be disregarded.
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 sus-
pended 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 automati-
cally cleared. The user can then send an acknowledge
bit at the end of reception, by setting the acknowledge
sequence enable bit, ACKEN (SSPCON2<4>).
9.2.12.1 BF STATUS FLAG
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.
9.2.12.2 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.
9.2.12.3 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).
1999 Microchip Technology Inc.
DS30292B-page 83
ETC [ ETC ]
