ata6616 ATMEL Corporation, ata6616 Datasheet - Page 142

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

DRAFT
Using the Input Capture unit in any mode of operation when the TOP value (resolution) is
actively changed during operation, is not recommended.
Measurement of an external signal’s duty cycle requires that the trigger edge is changed after
each capture. Changing the edge sensing must be done as early as possible after the ICR1
Register has been read. After a change of the edge, the Input Capture Flag (ICF1) must be
cleared by software (writing a logical one to the I/O bit location). For measuring frequency only,
the clearing of the ICF1 flag is not required (if an interrupt handler is used).
4.13.7
Output Compare Units
The 16-bit comparator continuously compares TCNT1 with the Output Compare Register
(OCR1A/B). If TCNT equals OCR1A/B the comparator signals a match. A match will set the Out-
put Compare Flag (OCF1A/B) at the next timer clock cycle. If enabled (OCIE1A/B = 1), the
Output Compare Flag generates an Output Compare interrupt. The OCF1A/B flag is automati-
cally cleared when the interrupt is executed. Alternatively the OCF1A/B flag can be cleared by
software by writing a logical one to its I/O bit locations. The Waveform Generator uses the match
signal to generate an output according to operating mode set by the Waveform Generation
mode (WGM13:0) bits and Compare Output mode (COM1A/B1:0) bits. The TOP and BOTTOM
signals are used by the Waveform Generator for handling the special cases of the extreme val-
ues in some modes of operation
(See “Modes of Operation” on page
147.)
A special feature of Output Compare unit A allows it to define the Timer/Counter TOP value (i.e.,
counter resolution). In addition to the counter resolution, the TOP value defines the period time
for waveforms generated by the Waveform Generator.
Figure 4-47
shows a block diagram of the Output Compare unit. The elements of the block dia-
gram that are not directly a part of the Output Compare unit are gray shaded.
ATA6616/ATA6617 [Preliminary]
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9132A–AUTO–10/08