SC9351 Просмотр технического описания (PDF) - Silan Microelectronics

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SC9351

AUDIO SYSTEM CONTROL MCU

Silan Microelectronics 

SC9351

3.2 Low-frequency operating mode

In this mode, 75KHz is selected to provide clock for CPU, RTC and all the other function modules and operating

mode can be switched from low-frequency to high-frequency or other modes through program setting.

Note: 1. 12MHz oscillator needs to be closed by software after MCU being switched to low-frequency operating

mode.

2. High-frequency oscillator needs to be open first by software for at least 1ms until it is stable when

operating mode is switched from low-frequency to high-frequency.

3.3 Sleep mode

In this mode, the clock for CPU, WDT, I2C, SPI, UART and ADC is closed, while oscillator still works and TIMER,

RTC, IO port and interrupt system still work under clock.

CPU can be waken up by allowed interrupt events caused by external interrupt, RTC, or TIMER and back to

former operating mode to execute the corresponding interrupt service routine.

3.4 Power-down hold mode

This mode is provided only when the chip adopts internal LDO(this operating mode is not available when

adopting external LDO). After LDO is closed, CPU, 64Kx8FLASH, 8Kx8RAM, 256x8RAM, I2C, SPI, UART, ADC,

TIMER and WDT are powered down because of no 2.5V supply voltage, while 12MHz/75KHz oscillator, RTC,

64x8RAM, IO port and external interrupt extension modules fed by external power supply still work.

In this mode, 75KHz oscillator provides clock for RTC; 75KHz or 12MHz oscillator provides clock for IO, interrupt

extension module intc_e. RTC and external interrupt can wake up LDO and reset CPU to back to former

operating mode.

Data can be saved in 64x8RAM in this mode.

4. Introduction to function module

4.1 Clock system

There are two oscillators and 75KHz oscillator provides clock for low-frequency operating, 12MHz oscillator

provides clock (12MHz/6MHz) for high-frequency operating.

‹ 75KHz and 12MHz oscillators are programmable control.

‹ In power-down hold mode, 12MHz oscillator can be closed and 75KHz oscillator provides clock for

RTC and external extension module.

Note: unless otherwise specified, the clock source mentioned below is 12MHz or 75KHz.

4.2 Reset control

There are power-on reset/external keypress reset, low voltage detect reset functions. What’s more, RTC interrupt

and external interrupt will also generate reset signal in power-down hold mode to reset CPU to come back to

operating mode.

‹ In power-down hold mode, external interrupt and RTC interrupt will generate reset signal to wake up

LDO and reset CPU, which has no effect on register value of RTC, oscillator control, clock control

and interrupt extension control, etc. About 15ms time delay is needed for LDO stable.

‹ In other operating modes (high-frequency, low-frequency, Sleep), LDO is working normally and

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

Http: //www.silan.com.cn

REV:1.0 2009.02.16

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