R8CSLASH15 datasheet(56/277 Pages) RENESAS

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R8C/14 Group, R8C/15 Group

9. Clock Generation Circuit

Rev.2.10

Jan 19, 2006

Page 44 of 253

REJ09B0164-0210

Figure 9.6

HRA1 and HRA2 Registers

High-speed On-Chip Oscillator Control Register 1

(1)

Symbol

Address

After Reset

HRA1

0021h

When Shipping

NOTES :

1. Set the PRC0 bit in the PRCR register to “1” (w rite enable) before rew riting to this register.

Function

The frequency of high-speed on-chip oscillator is adjusted w ith bits 0 to 7.

High-speed on-chip oscillator frequency = 8MHz

(HRA1 register = value w hen shipping ; fRING-fast mode 0)

Set the value of the HRA1 register to smaller (minimum value : 00h), the frequency w ill be

higher

Set the value of the HRA1 register to larger (maximum value : FFh), the frequecny w ill be

low er

b3 b2 b1 b0

b7 b6 b5 b4

High-Speed On-Chip Oscillator Control Register 2

(1)

Symbol

Address

After Reset

HRA2

0022h

00h

Bit Symbol

Bit Name

Function

NOTES :

1. Set the PRC0 bit in the PRCR register to “1” (w rite enable) before rew riting to this register.

High-speed on-chip oscillator frequency = 8MHz (HRA1 register = value w hen shipping)

If fRING-fast mode 0 is sw itched to fRING-fast mode 1, frequency w ill increase 1.5 times.

If fRING-fast mode 0 is sw itched to fRING-fast mode 2, frequency w ill increase 0.5 times.

—

(b4-b2)

Reserved Bit

Set to “0”

—

(b7-b5)

—

Nothing is assigned. When w rite, set to “0”.

When read, its content is “0”.

HRA20

HRA21

High-Speed On-Chip Oscillator Mode

Select Bit

b1 b0

0 0 : fRING-fast mode 0(2)

0 1 : fRING-fast mode 1(3)

1 0 : fRING-fast mode 2(4)

1 1 : Do not set

b3 b2 b1 b0

b7 b6 b5 b4

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