HD6417727BP160CV Datasheet, PDF (335/1098 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/ SH7700 Series

Section 10 On-Chip Oscillation Circuits
10.8.4 Using Interval Timer Mode
When operating in interval timer mode, interval timer interrupts are generated at every overflow of
the counter. This enables interrupts to be generated at set periods.
1. Clear the WT/IT bit in the WTCSR register to 0, set the type of count clock in the CKS2 to
CKS0 bits, and set the initial value of the counter in the WTCNT counter.
2. Set the TME bit in WTCSR to 1 to start the count in interval timer mode.
3. When the counter overflows, the WDT sets the IOVF flag in WTCSR to 1 and an interval
timer interrupt request is sent to INTC. The counter then resumes counting.
10.9 Notes on Board Design
When Using an External Crystal Resonator: Place the crystal resonator, capacitors CL1 and
CL2, and damping resistor R close to the EXTAL and XTAL pins. To prevent induction from
interfering with correct oscillation, use a common grounding point for the capacitors connected to
the resonator, and do not locate a wiring pattern near these components.
Avoid crossing
signal lines
CL1
CL2
EXTAL
R
XTAL
SH7727
Note: The values for CL1, CL2, and the damping resistance should be determined after
consultation with the crystal resonator manufacturer.
Figure 10.4 Points for Attention when Using Crystal Resonator
Rev.6.00 Mar. 27, 2009 Page 277 of 1036
REJ09B0254-0600