em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 50

• 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
40 •
In Timer mode, counting up is performed using the internal clock (rising edge trigger).
When the contents of the up-counter match the TCR3, then interrupt is generated and
the counter is cleared. Counting up resumes after the counter is cleared.
In Counter mode, counting up is performed using an external clock input pin (TC3
pin). When the contents of the up-counter match the TCR3, 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. The contents of TCR3 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 reset. A TC3 interrupt is generated each time the /PDO
output is toggled.
TC3 Interrupt
Clock source
Up-counter
/PDO Pin
TCR3
F/F
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Figure 6-5a Timer / Counter 3 Configuration
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Figure 6-5b PDO Mode Timing Chart
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(This specification is subject to change without further notice)
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Product Specification (V1.0) 05.05.2010
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