IST8310 datasheet(8)

IST 8310 datasheet 完整版

IST8310

IST8310 Datasheet, Version 1.2

8

3 Operational Modes and Functional Descriptions

3.1 Operation modes

IST8310 has following operation modes:

(1) Stand-By Mode

(2) Single Measurement Mode

(3) Self-Test Mode

3.1.1 Stand-By Mode

The initial mode (after power on) of IST8310 is Stand-By Mode. In Stand-By Mode, all internal circuits are off (except oscillator and regulator). All registers can be accessed in Stand-By Mode. Data stored in Read/Write registers remains as last state. Registers can be reset by soft reset or hard reset (through RSTN pin).

As initial setting, please set Pulse Duration Control Register, PDCTNL(0x42) = 11000000b (C0H) for performance optimization. For low noise performance, please set Average Control Register, AVGCNTL(0x41) = 00100100b (24H) for more internal average times. The minimum waiting time between two measurements under low noise performance setup is 6ms (166Hz).

3.1.2 Single Measurement Mode

In Single Measurement Mode, the measured data is stored in data registers then IST8310 transits to Stand-By Mode automatically. On transition to Stand-By Mode, Control register 1(CNTL1[3:0]) turns to “0000”. At the same time, DRDY bit in STA T1 register turns to “1”. This is called “data ready”. When any of the measurement data registers or STA T2 register is read, DRDY bit turns to “0”. For the next measurement, user needs to set Control register 1(CNTL1[3:0]) to “0001” again. The minimum waiting time between two measurements in default setup is 5ms (200Hz).

Please noted in IST8310, ultra-low noise performance is obtained through soft-averaging in driver. Please contact iSentek for technical details.

3.1.3 Self-Test Mode

Self-Test mode is used to check if the 3-axis outputs read in Single Measurement Mode are correct. It is activated by setting Self-Test Register (0x0C) to 40h; then all 3-axis outputs will change their polarity. User can check the 3-axis output values before and after activating Self-Test Mode; if the absolute values are the same, then the IC is working correctly. It can be turned off by setting Self-Test Register (0x0C) to 00h.