em78p809n ELAN Microelectronics Corp, em78p809n Datasheet - Page 49

• Manufacturer Part Number: em78p809n
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 07.26.2005
(This specification is subject to change without further notice)
TC4 pin
fc/2
fc/2
fc/2
7
3
11
4.11.1 Timer Mode
4.11.2 Counter Mode
4.11.3 PDO Mode
TC4CK
In Timer mode, counting up is performed using the internal clock. When the contents of
the up-counter matched with the TCR4, then interrupt is generated and the counter is
cleared. Counting up resumes after the counter is cleared.
In Counter mode, counting up is performed on the rising edge of the external clock
input pin (TC4 pin). When the contents of the up-counter matched with the TCR4, then
interrupt is generated and the counter is cleared. Counting up resumes after the
counter is cleared.
In Programmable Divider Output (PDO) mode, counting up is performed using the
internal clock.
up-counter. The F/F output is toggled and the counter is cleared each time a match is
found. The F/F output is inverted and output to /PDO pin. This mode can generate
50% duty pulse output. The F/F can be initialized by the program and it is initialized to
“0” during a reset. A TC4 interrupt is generated each time the /PDO output is toggled.
MUX
TC4 Interrupt
Source Clock
TC4S
3
TC4CR
Up-counter
/PDO Pin
TCR4
F/F
8-bit Up-counter
The contents of TCR4 are compared with the contents of the
TCR4
0
Clear
n
Fig. 25. Timer/Counter 4 Configuration
1
Fig. 26.Timing Chart for PDO Mode
2
TC4M (1,1)
3
Comparator
Overflow
Match
n-1
n
0
1
TC4M(1,*)
n-1
TC4FF
n
0
1
8-Bit Microcontroller
n-1
Clear
Toggle
Set
F/F
TC4 Interrupt
n
Q
EM78P809N
0
/PWM, /PDO Pin
1
2
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