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AS3900

Data Sheet - Detail ed Description

8.3.2 Handling the Link Manager

In general there are three different actions to operate the link manager.

Setting register

Sending direct commands

Handling interrupts

8.3.2.1 Setting Registers

The AS3900 has a MAIN register with 82bytes and a SHADOW register with 22 bytes. All configuration registers are readable and writable and

can be directly accessed via their register address. The registers are non volatile as long as the supply voltage is not decreased below the

specified minimum level of 2.0V. The two registers contain blocks for configuration, bits for setting direct commands, status bits, an ID table,

different data buffers as well as an interrupt table.

The complete register maps are directly addressable via the SDI interface that features:

Reading of a single register byte

Reading of register data with auto-incrementing address

Writing of a single register byte

Writing of register data with auto-incrementing address

8.3.2.2 Sending Direct Commands

The AS3900 can be directed via direct Commands that are executed via the SDI interface. With the direct Commands often used features of the

device can be activated or deactivated. Some of the commands can also be accessed via the register maps.

8.3.2.3 Handling Interrupt

Different interrupts are set by the link manager according to certain events in the interrupt registers (in the MAIN register). 16 possible interrupt

sources can be enabled or disabled by the use of the Interrupt Mask Register.

If one of the enabled interrupt conditions is met, the AS3900 apply a HIGH level on the IRQ pin. The IRQ level is set to LOW level after reading

the interrupt register. The MCU reads the interrupt register to distinguish between the different interrupt sources. The interrupt registers are reset

automatically after reading.

8.4 Digital Interface

The interface is used for the serial communication between the Microcontroller and the AS3900.The maximum operation frequency of the Serial

Data Interface (SDI) is 2MHz. The Interrupt Interface (IRQ) provides a CMOS compatible HIGH level at the occurrence of an interrupt. This level

will be set to LOW if one of the interrupt registers is read. In active modes of the AS3900, a register selectable frequency is provided at the pin

MCU_CLK. A typical connection to the MCU is shown in Figure 13

Figure 13. Microcontroller Interface

MCU

AS3900

INT0

XTAL1

IRQ

MCU_CLK

SDATAO

SEN

SCLK

SDATAI

MISO

GPIO1

SCLK

MOSI