User’s Manual U13850EJ6V0UD
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CHAPTER 6 CLOCK GENERATION FUNCTION
6.1 Outline
The clock generator is a circuit that generates the clock pulses that are supplied to the CPU and peripheral
hardware. There are two types of clock oscillators.
(1) Main clock oscillator
The oscillator of V850/SB1 has an oscillation frequency of 2 to 20 MHz. The oscillator of the A and B versions of
the V850/SB2 has an oscillation frequency of 2 to 12.58 MHz and the oscillator of the H version of the V850/SB2
has an oscillation frequency of 2 to 19 MHz. Oscillation can be stopped by executing a STOP instruction or by
setting the processor clock control register (PCC). Oscillation is also stopped during a reset.
In IDLE mode, supplying the peripheral clock to the clock timer only is possible. Therefore, in IDLE mode, it is
possible to operate the clock timer without using the subclock oscillator.
Cautions 1. When the main oscillator is stopped by inputting a reset or executing a STOP instruction,
the oscillation stabilization time is secured after the stop mode is released. This
oscillation stabilization time is set via the oscillation stabilization time selection register
(OSTS). The watchdog timer is used as the timer that counts the oscillation stabilization
time.
2. If the main clock halt is released by clearing MCK to 0 after the main clock is stopped by
setting the MCK bit in the PCC register to 1, the oscillation stabilization time is not
secured.
(2) Subclock oscillator
This circuit has an oscillation frequency of 32.768 kHz. Its oscillation is not stopped when the STOP instruction
is executed, neither is it stopped when a reset is input.
When the subclock oscillator is not used, the FRC bit in the processor clock control register (PCC) can be set to
disable use of the internal feedback resistor. This enables the current consumption to be kept low in the STOP
mode.
Содержание V850/SB1
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