EM6812F2TP24B datasheet(24/81 Pages) EMMICRO

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EM6812

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8.2

High frequency clock source

8.2.1

RC oscillator

The RC oscillator is the main clock generator of the high frequency domain. Its function is based on internal elements only.

An 8-bit trim register is provided to allow precise frequency adjustment based on known timing functions (software

Frequency Locked Loop FLL). The RC Osc is switched on by default on system startup and after any reset on its base

frequency of 1MHz. The Pre-Divider is set to /8 which results in a CPU and peripheral clock frequency of 125KHz (typ).

•

Frequency range: 1MHz or 10MHz. Selectable with bit FreqRange in register RegSys1.

•

Frequency division by 1, 2, 4 or 8. Selectable with bits RCDiv[1:0] in register RegSys2.

•

RC trimming: Range

± ~40%. Coded on 8 bits Trim[7:0] in register RegTrimRC.

Figure 16. Overlapping RC Oscillator trimming regions (75kHz to 14MHz)

The user may generate almost any frequency from typ. ~75kHz up to ~14MHz continuously with the 3 combinations

mentioned above. The F2 clock mainly depends on the selected frequency range, divider setting and trimm value.

Table 18. Clock selection after Pre-Division (signal F2 in Figure 15)

RC oscillator @ 1 MHz

FreqRange = 0 in RegSys1

RC oscillator @ 10 MHz

FreqRange = 1 in RegSys1

Divide by 8

Divide by 4

Divide by 2

Divide by 1

Divide by 8

Divide by 4

Divide by 2

Divide by 1

RCDiv[1:0]

RC trimming: minimum frequency Trim[7:0] = 00

75kHz

150kHz

300kHz

0.6MHz

0.75MHz

1.5MHz

3MHz

6MHz

RC trimming: nominal frequency Trim[7:0] = 7F (default)

125 kHz

250kHz

500kHz

1MHz

1.25MHz

2.5MHz

5MHz

10MHz

RC trimming: maximum frequency Trim[7:0] = FF

175kHz

350kHz

700kHz

1.4MHz

1.75MHz

3.5MHz

7MHz

14MHz

Typ 1MHz

Frequency after Pre-Division

Typ -40%

Typ +40%

Typ 500kHz

Typ 250kHz

Typ 125kHz

Min. 75kHz(RC=1MHz)

Max. 1.4MHz(RC=1Mhz)

RC 1MHz

Frequency after Pre-Division

Typ 10MHz

Typ -40%

Typ +40%

Typ 5MHz

Typ 2.5MHz

Typ 1.25MHz

Min 750kHz(RC=10MHz)

Max. 14MHz(RC=10Mhz)

RC 10MHz

EM6812F2TP24B 数据表(PDF) 24 Page - EM Microelectronic - MARIN SA

EM6812F2TP24B 数据表(HTML) 24 Page - EM Microelectronic - MARIN SA

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