PIC16F639 Microchip Technology Inc., PIC16F639 Datasheet - Page 57

• Manufacturer Part Number: PIC16F639
• Description: 8/14-pin Flash-based, 8-bit Cmos Microcontrollers With Nanowatt Technology
• Manufacturer: Microchip Technology Inc.

4.2.4.5
Figure 4-5 shows the diagram for this pin. The RA4 pin
is configurable to function as one of the following:
• a general purpose I/O
• a Timer1 gate input
• a crystal/resonator connection
• a clock output
FIGURE 4-5:
© 2007 Microchip Technology Inc.
Data Bus
WPUDA
WPUDA
PORTA
PORTA
TRISA
TRISA
WDA
WDA
IOCA
IOCA
WR
WR
WR
WR
WR
Note 1:
RD
RD
RD
RD
RD
Interrupt-on-
change
2:
D
D
D
D
D
T1G To Timer1
CK
CK
CK
CK
CK
Oscillator modes are XT, HS, LP, LPTMR1 and
CLKOUT Enable.
With CLKOUT option.
RA4/T1G/OSC2/CLKOUT
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
BLOCK DIAGRAM OF RA4
OSC1
F
OSC
RAPU
RC/EC
INTOSC/
CLKOUT
CLKOUT
Enable
CLK
Enable
/4
RD PORTA
CLKOUT
Enable
Oscillator
XTAL
(1)
Circuit
Q
Q
1
0
(2)
Modes
EN
EN
D
D
V
V
Q1
SS
V
DD
V
DD
SS
Weak
Weak
I/O pin
PIC12F635/PIC16F636/639
4.2.4.6
Figure 4-6 shows the diagram for this pin. The RA5 pin
is configurable to function as one of the following:
• a general purpose I/O
• a Timer1 clock input
• a crystal/resonator connection
• a clock input
FIGURE 4-6:
Data Bus
WPUDA
WPUDA
PORTA
PORTA
TRISA
TRISA
WDA
WDA
IOCA
IOCA
WR
WR
WR
WR
RD
RD
RD
WR
Interrupt-on-
RD
RD
change
Note 1:
D
D
D
D
D
2:
T1G To Timer1
CK
CK
CK
CK
CK
RA5/T1CKI/OSC1/CLKIN
Oscillator modes are XT, HS, LP and LPTMR1.
When using Timer1 with LP oscillator, the
Schmitt Trigger is bypassed.
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
BLOCK DIAGRAM OF RA5
OSC2
RAPU
CLK
INTOSC
RD PORTA
Mode
Oscillator
Circuit
(1)
Q
Q
Modes
EN
EN
DS41232D-page 55
D
D
V
V
Q1
DD
SS
V
V
DD
SS
Weak
Weak
I/O pin
(2)