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AS8510

Datasheet - Detailed Descr i p ti on

7.4.4 Standby Mode2 (SBM2)

Standby Mode 2 is an extension of the Standby Mode1 to achieve even a lower power in the data acquisition system by providing interrupt to the

microcontroller only when the data sample exceeds the set current threshold. The Standby Mode can be entered only through the STOP state.

Transition to SBM2 mode occurs when the “START BIT” D0 of Mode Control register MOD_CTL_REG in Table 33 is set to “1” and Mode Control

Bits D7,D6 to “1,1” through SPI. In this mode the date rate is programmable with the time of Ta in the Ta control registers B, C. The data sample

is made available and an interrupt signal is generated on INT pin only when the input signal exceeds the threshold set in Current Threshold

Registers D,E. It should be noted here that the data is stable for Ta secs. The functionality is illustrated in Figure 8.

Figure 8. Standby Mode 2

7.5 Reference-Voltage

Band gap-reference voltage is used for the ADC as a reference and for the generation of the current for external temperature measurement.

7.6 Oscillators

A High-speed oscillator (HS) generates the oversampling clock. For internal state machine and Interrupt generation, a low-speed Oscillator (LS)

is also available.

7.7 Power-On Reset

The AS8510 has PORs, APOR and DPOR on analog and digital power supplies respectively. On PORs of both supplies, initialization sequence

happens and the system status is shown in state diagram (see Figure 4).

As shown in the state diagram, the system is in RESET state until DPOR output goes to logic HIGH and subsequently until APOR output goes to

logic HIGH. Once analog power supply is available, the system goes into OTP_INT state and loads the default values into the control and data

registers and goes into STOP state. If analog POR, APOR goes low at any time, the system goes into RESET state. In the STOP state, the

AS8510 can be programmed and by giving start command it starts working following the state machine.

ADC

t

Start SBM2

I

I

MCU

|I| > I Threshold

INT

Channel

DATA Register

DATA – A1

DATA – A0

DATA – A2

DATA – A3