em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 38

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

EM78F648/644/642/641/548/544/542/541N
8-Bit Microcontroller
28 •
In Timer mode, counting up is performed using internal clock. When the contents of
the up-counter match the TCR2 (TCR2DH+TCR2DL), the interrupt is then generated
and the counter is cleared. Counting up resumes after the counter is cleared.
In Counter mode, counting up is performed using external clock input pin (TC2) and
either rising or falling can be selected by setting TC2ES. When the contents of the
up-counter match the TCR2 (TCR2DH+TCR2DL), then interrupt is generated and the
counter is cleared. Counting up resumes after the counter is cleared.
In Window mode, counting up is performed on a rising edge of the pulse that is
logical AND of an internal clock and the TC2 pin (window pulse). When the contents
of up-counter match with the TCR2 (TCR2DH+TCR2DL), then interrupt is generated
and the counter is cleared. The frequency (window pulse) must be slower than
the selected internal clock.
In Writing to the TCR2DL, comparison is inhibited until TCR2DH is written.
TC2 Interrupt
Clock source
Up-counter
TC2 Interrupt
Up-counter
TC2 Pin
TCR2
TCR2
n
0
Figure 6-4c Counter Mode Timing Diagram
n
Figure 6-4b Timer Mode Timing Diagram
0
1
1
2
2
(This specification is subject to change without further notice)
3
3
4
4
5
Product Specification (V1.0) 05.05.2010
n-2
n-3
match
n-2
match
n-1
n-1
n
0
n
clear counter
0
1
clear counter
1
2
2
3
3