PIC16CR66-04I/TQ View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
PIC16CR66-04I/TQ Datasheet PDF : 336 Pages
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PIC16C6X
5.5 PORTE and TRISE Register
Applicable Devices
61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67
PORTE has three pins, RE2/CS, RE1/WR, and
RE0/RD which are individually configurable as inputs
or outputs. These pins have Schmitt Trigger input buff-
ers.
I/O PORTE becomes control inputs for the micropro-
cessor port when bit PSPMODE (TRISE<4>) is set. In
this mode, the user must make sure that the
TRISE<2:0> bits are set (pins are configured as digital
inputs). In this mode the input buffers are TTL.
Figure 5-9 shows the TRISE register, which controls
the parallel slave port operation and also controls the
direction of the PORTE pins.
FIGURE 5-8: PORTE BLOCK DIAGRAM
(IN I/O PORT MODE)
Data
bus
WR
PORT
DQ
CK
I/O pin(1)
WR
TRIS
Data Latch
DQ
CK
TRIS Latch
Schmitt
Trigger
input
buffer
RD TRIS
Q
D
RD PORT
ENEN
Note 1: I/O pins have protection diodes to VDD and VSS.
FIGURE 5-9: TRISE REGISTER (ADDRESS 89h)
R-0
IBF
bit7
bit 7 :
bit 6:
bit 5:
bit 4:
bit 3:
bit 2:
bit 1:
bit 0:
R-0
OBF
R/W-0 R/W-0
U-0
IBOV PSPMODE —
R/W-1
bit2
R/W-1
bit1
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
R/W-1
bit0
bit0
R = Readable bit
W = Writable bit
U = Unimplemented bit,
read as ‘0’
- n = Value at POR reset
OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written word
0 = The output buffer has been read
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
PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel slave port mode
0 = General purpose I/O mode
Unimplemented: Read as '0'
PORTE Data Direction Bits
Bit2: Direction Control bit for pin RE2/CS
1 = Input
0 = Output
Bit1: Direction Control bit for pin RE1/WR
1 = Input
0 = Output
Bit0: Direction Control bit for pin RE0/RD
1 = Input
0 = Output
DS30234D-page 58
© 1997 Microchip Technology Inc.
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