
2001 Microchip Technology Inc.
DS30292C-page 37
PIC16F87X
REGISTER 3-1:
TRISE REGISTER (ADDRESS 89h)
R-0
R/W-0
U-0
R/W-1
IBF
OBF
IBOV
PSPMODE
—
Bit2
Bit1
Bit0
bit 7
bit 0
Parallel Slave Port Status/Control Bits:
bit 7
IBF: Input Buffer Full Status bit
1
= A word has been received and is waiting to be read by the CPU
0
= No word has been received
bit 6
OBF: Output Buffer Full Status bit
1
= The output buffer still holds a previously written word
0
= The output buffer has been read
bit 5
IBOV: Input Buffer Overflow Detect bit (in Microprocessor mode)
1
= A write occurred when a previously input word has not been read (must be cleared in
software)
0
= No overflow occurred
bit 4
PSPMODE: Parallel Slave Port Mode Select bit
1
= PORTD functions in Parallel Slave Port mode
0
= PORTD functions in general purpose I/O mode
bit 3
Unimplemented: Read as '0'
PORTE Data Direction Bits:
bit 2
Bit2: Direction Control bit for pin RE2/CS/AN7
1
= Input
0
= Output
bit 1
Bit1: Direction Control bit for pin RE1/WR/AN6
1
= Input
0
= Output
bit 0
Bit0: Direction Control bit for pin RE0/RD/AN5
1
= Input
0
= Output
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
- n = Value at POR
’1’ = Bit is set
’0’ = Bit is cleared
x = Bit is unknown