PIC16C63A/65B/73B/74B
FIGURE 5-7:
PORTE BLOCK DIAGRAM
5.5
PORTE and TRISE Register
Data
Bus
Note 1: The PIC16C63A and PIC16C73B do not
provide PORTE. The PORTE and TRISE
registers are not implemented.
D
Q
I/O pin(1)
WR
Port
CK
Data Latch
2: The PIC16C63A/65B does not provide an
A/D module. A/D functions are not imple-
mented.
D
Q
WR
TRIS
PORTE has three pins: RE0/RD/AN5, RE1/WR/AN6
and RE2/CS/AN7, which are individually configured as
inputs or outputs. These pins have Schmitt Trigger
input buffers.
Schmitt
Trigger
Input
CK
TRIS Latch
Buffer
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) and that register ADCON1 is configured for dig-
ital I/O. In this mode, the input buffers are TTL.
RD TRIS
Q
D
EN
EN
RD Port
Register 5-1 shows the TRISE register, which also con-
trols the parallel slave port operation.
PORTE pins may be multiplexed with analog inputs
(PIC16C74B only). The operation of these pins is
selected by control bits in the ADCON1 register. When
selected as an analog input, these pins will read as ’0’s.
Note 1: I/O pins have protection diodes to VDD and VSS.
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
Note: On a Power-on Reset, these pins are con-
figured as analog inputs and read as ‘0’s.
TABLE 5-9:
Name
PORTE FUNCTIONS
Bit#
Buffer Type
Function
(1)
RE0/RD/AN5
bit0
ST/TTL
Input/output port pin or read control input in Parallel Slave Port mode or analog
input:
RD
1 = Idle
0 = Read operation. Contents of PORTD register is output to PORTD
I/O pins (if chip selected).
(1)
RE1/WR/AN6
RE2/CS/AN7
bit1
bit2
ST/TTL
Input/output port pin or write control input in Parallel Slave Port mode or analog
input:
WR
1 = Idle
0 = Write operation. Value of PORTD I/O pins is latched into PORTD
register (if chip selected).
(1)
ST/TTL
Input/output port pin or chip select control input in Parallel Slave Port mode or
analog input:
CS
1 = Device is not selected
0 = Device is selected
Legend: ST = Schmitt Trigger input, TTL = TTL input
Note 1: Input buffers are Schmitt Triggers when in I/O mode and TTL buffers when in Parallel Slave Port mode.
2000 Microchip Technology Inc.
DS30605C-page 35
MICROCHIP [ MICROCHIP ]
