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_PLS_CNT_CFG (0x1E)

This byte contains command ID (command type). It must be set to 0x1E.

Byte 1: ECHO

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

Byte 2: PLS_CNT_NUMBER

The ID number of the pulse counter:

• 0 – pulse counter on A.3 pin;

• 1 – pulse counter on A.4 pin.

Bytes 3..7: Reserved

These bytes are reserved for future usage and must be set to 0.

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

Byte 0: GPIO_GET_PLS_CNT_CFG (0x1E)

Response ID (response type). This byte will contain 0x1E.

Byte 1: ECHO

Echo byte copied from the corresponding command. It is used to associate the response with the specific command.

Byte 2: ST

Status of the command execution:

• GPIO_ST_SUCCESS (0x00) – Pulse counter configuration has succesfully been retrieved;

• GPIO_ST_INVALID_PLS_CNT_NUMBER (0x0A) – Invalid ID of the pulse counter has been specified (only 0 and 1 values are valid).

Byte 3:

Bits 7..3	Bit 2	Bit 1	Bit 0
Reserved	SUSPENDED	ON	PLS_CNT_NUMBER

Bits 7..3: Reserved

These bits are reserved for future usage.

Bit 2: SUSPENDED

Pulse counter state:

• 0 – pulse counter is running;

• 1 – pulse counter is in suspended state. It will not run until you send the GPIO_RESUME_PLS_CNT command.

Bit 1: ON

The pulse counter state (on/off):

• 1 – the pin is switched to the pulse counter mode;

• 0 – the pulse counter mode is switched off on the pin.

Bit 0: PLS_CNT_NUMBER

The ID number of the pulse counter:

• 0 – pulse counter on A.3 pin;

• 1 – pulse counter on A.4 pin.

Byte 4:

Bits 7..4	Bit 3	Bit 2	Bit 1	Bit 0
PLS_CNT_MODE	Reserved	EV_MATCH	Reserved	EV_OVERFLOW

Bits 7..4: PLS_CNT_MODE

The mode in which pulse counter operates:

• GPIO_PLS_CNT_MODE_FREE_RUN(0) – pulses are counted until maximum number of pulses (16,777,215) is reached. For more detailed information see Section 11.1.1, “Free Run Mode”.

• GPIO_PLS_CNT_MODE_TIME_BASED(1) – pulses are counted only during user-defined time period. For more detailed information see Section 11.1.2, “Time Based Mode”.

• GPIO_PLS_CNT_MODE_PULSE_BASED(2) – pulses are counted until user-defined number of pulses is detected. For more detailed information see Section 11.1.3, “Pulse Based Mode”.

Bit 3: Reserved

This bit is reserved for future usage.

Bit 2: EV_MATCH

• 1 – USB-I/O adapter will send the GPIO_EV_PLS_CNT event either when the time period is exceeded (Time Based Mode) or when the threshold number of pulses is detected (Pulse Based Mode). For more detailed information see Section 11.2, “Pulse Counter Event”;

• 0 – the event is not generated when pulse counter limits are reached.

Bit 1: Reserved

This bit is reserved for future usage.

Bit 0: EV_OVERFLOW

• 1 – USB-I/O adapter will send the GPIO_EV_PLS_CNT event when maximum number of pulses is reached. For more detailed information see Section 11.2, “Pulse Counter Event”;

• 0 – the event is not generated when maximum number of pulses is reached.

Byte 5: REPEAT

The repeat interval for GPIO_EV_PLS_CNT event generation. If this byte is non-zero, GPIO-24 adapter sends events each REPEAT*10 ms. For more detailed information see Section 11.2, “Pulse Counter Event”.

Bytes 6..7: Reserved

These bytes are reserved for future usage.