R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 46

• Manufacturer Part Number: R5F21133DFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES
• Manufacturer: RENESAS [Renesas Technology Corp]

R8C/13 Group
Rev.1.20
REJ09B0111-0120
6.2 On-Chip Oscillator Clock
6.2.1 Low-Speed On-Chip Oscillator Clock
6.2.2 High-Speed On-Chip Oscillator Clock
This clock is supplied by a on-chip oscillator. There are two kinds of on-chip oscillator: high-speed on-
chip oscillator and low-speed on-chip oscillator. These oscillators are selected by the bit HR01 bit in
the HR0 register.
Jan 27, 2006
The clock derived from the low-speed on-chip oscillator is used as the clock source for the CPU
clock, peripheral function clock, f
After reset, the on-chip oscillator clock derived from low-speed on-chip oscillator by divided by 8 is
selected for the CPU clock.
If the main clock stops oscillating when the OCD1 to OCD0 bits in the OCD register are “11
lation stop detection function enabled), the low-speed on-chip oscillator automatically starts operat-
ing, supplying the necessary clock for the microcomputer.
The frequency of the low-speed on-chip oscillator varies depending on the supply voltage and the
operation ambient temperature. The application products must be designed with sufficient margin for
the frequency change.
The clock derived from high-speed on-chip oscillator is used as the clock source for the CPU clock,
peripheral function clock, f
After reset, the on-chip oscillator clock derived from high-speed on-chip oscillator is halted. The
oscillation is started by setting the HR00 bit in the HR0 register to “1” (high-speed on-chip oscillator
on). The frequency can be adjusted by the HR1 register.
The relationship between the value of HR1 register and the period of high-speed on-chip oscillator is
shown below. It is noted that the difference in delay between the bits should be adjusted by changing
each bit. Bit 7 should be set be “0”.
Period of high-speed on-chip oscillator = td(HR offset) + (64
b0 to b6 : Bits in HR1 register
b2 + 2
b1 + b0)
page 35 of 205
td(HR)
RING
, f
RING
RING128
, f
RING128
, and f
RING1-fast
and f
RING-S
.
.
b6 + 32
6.2 On-chip Oscillator Clock
b5 + 16
b4 + 8
2
” (oscil-
b3 + 4