USB-I/O Interface Adapter GPIO-24. Programmer's Reference Manual.

Command is an 8-byte array of the following format:

Byte 0: GPIO_GET_ADC_MODULE_CFG (0x25)

This byte contains command ID (command type). It should be set to 0x25.

Byte 1: ECHO

This byte is used to associate a response received from GPIO-24 adapter with a specific command. Response will contain exactly the same value in its echo byte.

Bytes 2..7: Reserved

These bytes are reserved for future usage.

Response is an 8-byte array of the following format:

Byte 0: GPIO_GET_ADC_MODULE_CFG (0x25)

This byte contains response ID (response type). This byte will contain 0x25.

Byte 1: ECHO

This byte is used to associate a response received from GPIO-24 adapter with a specific command. Response will contain exactly the same value in its echo byte.

Byte 2: ST

Status of the command execution:

• GPIO_ST_SUCCESS (0x00) – ADC module configuration has been succesfully retrieved.

Byte 3: ON

The ADC module state (on/off):

• 1 – the ADC module is turned on. The C.1, C.2, C.5, C.6 and B.3 pins are analog inputs (ADC channels);

• 0 – the ADC module is turned off. The ADC mode is switched off on the C.1, C.2, C.5, C.6 and B.3 pins.

Byte 4: VREF

This byte contains the value of reference voltage. You can use either USB-I/O adapter supply voltage (V_DD and V_SS) or the external reference voltage connected to C.6 (V_RefHi) and C.5 (V_RefLow) pins.

Bits 7..2	Bit 1	Bit 0
Reserved	VREF_LOW	VREF_HI

Bits 7..2: Reserved

These bits are reserved for future usage

Bit 1: VREF_LOW

The low reference voltage:

• 1 – the external voltage reference on C.5 pin is used as low reference voltage;

• 0 – the USB-I/O adapter negative supply voltage (V_SS) is used as low reference voltage.

Bit 0: VREF_HI

The high reference voltage:

• 1 – the external voltage reference on C.6 pin is used as high reference voltage;

• 0 – the USB-I/O adapter positive supply voltage (V_DD) is used as high reference voltage.

Bytes 5..7: Reserved

These bytes are reserved for future usage.