EM78P312N
8-Bit Microcontroller
TC4FF
TC4M (1,1)
TC4 Interrupt
F/F
/PWM, /PDO Pin
Clear
Set
11
fc/2
Clear
Q
TC4M(1,*)
fc/2 7
MUX
fc/2 3
Toggle
8-bit Up-counter
Overflow
Match
TC4 pin
Comparator
TC4CK
3
TC4S
TC4CR
TCR4
Fig. 5-24 Timer/Counter 4 Configuration
5.11.1 Timer Mode
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.
5.11.2 Counter Mode
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.
5.11.3 PDO Mode
In Programmable Divider Output (PDO) mode, counting up is performed using the
internal clock. The contents of TCR4 are compared with the contents of the
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.
Source Clock
Up-counter
TCR4
n
2
n-1
n
1
n-1
n
0
1
3
0
0
1
n-1
0
1
2
n
F/F
/PDO Pin
TC4 Interrupt
Fig. 5-25 Timing Chart for PDO Mode
40 •
Product Specification (V1.0) 10.03.2006
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
