High-Speed On-Chip Oscillator Control Register (Hococr) - Renesas RX100 Series User Manual

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High-Speed On-Chip Oscillator Control Register (HOCOCR)

Address(es): 0008 0036h

Value after reset:

Set the PRCR.PRC0 bit to 1 (write enabled) before rewriting this register.

Note 1. The HCSTP bit value after a reset is 0 when the HOCO oscillation enable bit in option function select register 1

(OFS1.HOCOEN) is 0. The HCSTP bit value after a reset is 1 when the OFS1.HOCOEN bit is 1.

Set the high-speed on-chip wait control register before setting this register.

HCSTP Bit (HOCO Stop)

This bit runs or stops the HOCO.

When changing the HCSTP bit from 1 to 0 (i.e. changing the HOCO clock from stopped to operating), confirm that the

OSCOVFSR.HCOVF flag is 1 before switching the system clock to the HOCO clock.

That is, a fixed time for stabilization of oscillation is required after the setting for HOCO operation. A fixed time is also

required for oscillation to stop after the setting to stop the oscillator. Accordingly, take note of the following limitations

when starting and stopping the oscillator.

 After stopping the HOCO, confirm that the OSCOVFSR.HCOVF flag is 0 before restarting the HOCO.

 Confirm that the HOCO is operating and that the OSCOVFSR.HCOVF flag is 1 before stopping the HOCO.

 Regardless of whether or not it is selected as the system clock, confirm that the OSCOVFSR.HCOVF flag is 1

before executing a WAIT instruction to place the MCU in software standby mode.

 After stopping the HOCO, confirm that the OSCOVFSR.HCOVF flag is 0 and execute a WAIT instruction before

entering software standby mode.

While the HOCO is selected by the SCKCR3.CKSEL[2:0] bits, do not set the HCSTP bit to 1 (HOCO is stopped).

R01UH0822EJ0100 Rev.1.00

Jul 31, 2019

0: HOCO is operating.

1: HOCO is stopped.

These bits are read as 0. The write value should be 0.

9. Clock Generation Circuit

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