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

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

Byte 0: GPIO_SET_PLS_CNT_CFG (0x1D)

This byte contains command ID (command type). It must be set to 0x1D.

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:

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. They must be set to 0.

Bit 2: SUSPENDED

Pulse counter state:

• 0 – pulse counter runs immediately after configuration.

• 1 – pulse counter will be 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. GPIO_GET_CFG and GPIO_GET_PIN_CFG commands will return GPIO_CFG_PLS_CNT (0x7) value for the pin. The pin can be used only by the pulse counter module;

• 0 – the pulse counter mode is switched off on the pin. GPIO_GET_CFG and GPIO_GET_PIN_CFG commands will return GPIO_CFG_NOT_CONFIGURED (0xf) value for the pin. The pin can be used by any module.

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 3:

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 pulse counter can be configured into one of three possible modes:

• 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. It must be set to 0.

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.

This bit is not used in Free Run Mode and must be set to 0.

Bit 1: Reserved

This bit is reserved for future usage and must be set to 0.

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 4: REPEAT

This byte defines 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 5..7: LIMIT

These bytes define pulse counter limits.

For the pulse counter in Time Based Mode these bytes define the time period in units of 10 ms up to 16,777,215 (167,772,150 ms or 46.5 h). Pulses will be counted only during this time period.

For the pulse counter in Pulse Based Mode these bytes define the threshold number of pulses up to 16,777,215. Pulses will be counted until this number is detected.

Byte 5: LIMIT[2] – least significant byte (low byte) of a pulse counter limit.

Byte 6: LIMIT[1] – middle byte of threshold a pulse counter limit.

Byte 7: LIMIT[0] – most significant byte (high byte) of a pulse counter limit.

For the pulse counter in Free Run Mode these bytes are not used and must be set to 0.

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

Byte 0: GPIO_SET_PLS_CNT_CFG (0x1D)

Response ID (response type). This byte will contain 0x1D.

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 has succesfully been configured;

• GPIO_ST_INVALID_PARAMETER (0x0A) – Unsupported pulse counter mode has been specified.

Bytes 3..7: Reserved

These bytes are reserved for future usage.