PIC16C774 Microchip Technology Inc., PIC16C774 Datasheet - Page 28

• Manufacturer Part Number: PIC16C774
• Description: 28/40-pin, 8-bit Cmos Microcontrollers W/ 12-bit A/d
• Manufacturer: Microchip Technology Inc.

PIC16C77X
FIGURE 3-2:
TABLE 3-1
TABLE 3-2
DS30275A-page 28
Name
RA0/AN0
RA1/AN1
RA2/AN2/V
RA3/AN3/V
RA4/T0CKI
RA5/AN4
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1: RA5 is reserved on the 28-pin devices, maintain this bit clear.
Address
05h
85h
9Fh
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by PORTA.
Note 1:
Data
bus
WR
Port
WR
TRIS
RD PORT
To A/D Converter
Note 1: I/O pins have protection diodes to V
PORTA<5>, TRISA<5> are reserved on the 28-pin devices, maintain these bits clear.
(1)
Name
PORTA
TRISA
ADCON1
V
D
D
Data Latch
TRIS Latch
SS
REF
REF
CK
CK
.
-/VRL
+/VRH
(1)
(1)
BLOCK DIAGRAM OF
RA1:RA0 AND RA5 PINS
PORTA FUNCTIONS
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Q
Q
Q
Q
RD TRIS
ADFM VCFG2
Bit 7
—
—
Bit#
bit0
bit1
bit2
bit3
bit4
bit5
Q
Bit 6
—
—
Analog
input
mode
EN
D
Buffer
TTL
TTL
TTL
TTL
ST
TTL
PORTA Data Direction Register
VCFG1 VCFG0
V
V
P
N
Bit 5
RA5
SS
DD
DD
Advance Information
and
I/O pin
TTL
input
buffer
Function
Input/output or analog input0
Input/output or analog input1
Input/output or analog input2 or V
voltage low
Input/output or analog input or V
reference voltage high
Input/output or external clock input for Timer0
Output is open drain type
Input/output or analog input
Bit 4
RA4
(1)
PCFG3
Bit 3
RA3
FIGURE 3-3:
PCFG2
Bit 2
RA2
Data
bus
WR
TRIS
WR
PORT
RD PORT
Note 1: I/O pin has protection diodes to V
TMR0 clock input
PCFG1
Bit 1
RA1
TRIS Latch
Data Latch
REF
D
D
CK
CK
REF
RD TRIS
BLOCK DIAGRAM OF
RA4/T0CKI PIN
+ input or output of internal
PCFG0
- input or internal reference
Bit 0
RA0
Q
Q
Q
Q
1999 Microchip Technology Inc.
--0x 0000
--11 1111
0000 0000
Value on:
Q
POR,
BOR
EN
Schmitt
Trigger
input
buffer
EN
D
V
N
SS
other resets
Value on all
SS
--0u 0000
--11 1111
0000 0000
I/O pin
only.
(1)