upd70f3422gj-gae-qs-ax Renesas Electronics Corporation., upd70f3422gj-gae-qs-ax Datasheet - Page 493

• Manufacturer Part Number: upd70f3422gj-gae-qs-ax
• Description: 32-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

Watch Timer (WT)
Chapter 14
14.5 Watch Calibration Timer Operation
The Watch Calibration Timer WCT is used to measure the time between two
successive occurrences of the Watch Timer WT0 underflow interrupt
INTWT0UV.
The WCT is supplied with the stable clock WCTCLK:
• WCTCLK = 4 MHz main oscillator, if PSM.CMODE = 1
• WCTCLK = 8 MHz PCLK1, if PSM.CMODE = 0
For further details refer to “Clock Generator“ on page 129.
The measured INTWT0UV interval time gives an indication about the accuracy
of the sub or ring oscillator. A correction value can be calculated to calibrate
WT0 and WT1 by changing their reload values.
The interval measurement can be performed by both WCT operating modes:
• Free-running mode
• Restart mode
If a timer overflow can occur during the interval measurement, take care for
regarding also the overflow flag TMC00.OVF00 for calculating the interval
correctly.
Preliminary User’s Manual U17566EE1V2UM00
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