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DCAPI TR122_GetTriggerInformation(DWORD *NumberOfTriggers, DWORD *Times);

This routine is called to validate a transient record and to determine the amount of data present. It is called

internally to the API as part of a display function. However, it can be called from a higher level application. If a

valid transient record is present in memory, this routine will return the number of segments filled with valid data and

an array of up to 32 time values at which the triggers occurred with respect to the first trigger. The first element in

the array will always contain a 0. The times will be a count of microseconds. The time values are full 32-bit

numbers, so as an exception to the general rule, to take advantage of the full range the calling program will need to

be able to interpret unsigned 32-bit numbers.

DCAPI TR122_SetTrigger(BYTE Source, double Level, BYTE Edge);

The trigger source parameters are set by this function. The source can be 0, 1, or 2 for external, channel 1, or

channel 2 respectively. The level can be –10 to +10 for source 0 and –100 to +100 for source 1 or 2. The trigger

level for the channel sources is similar to percentage of full scale above or below midscale. The edge argument

is 0 for falling and 1 for rising edge sensitivity.

DCAPI TR122_SetOffset(long AstractOffset1, long AbstractOffset2, BYTE Update);

The offset in electronic terms is another analog signal added to the incoming signal being measured. Each setting

of the front end attenuator can cause the offset electronics to behave differently. This method of setting offset takes

these items into account. The offset is an abstract value of 0 to 256 representing where the user would want the

offset to be in an 8-bit full scale range. If Update is true, this routine sets the offset analog voltages according to

these instructions and the current setting of the front end attenuator. The settings are also stored in the API. If the

attenuator settings are changed, this function can be called with Update false to install new offset analog voltages

based on offset instructions previously stored in the API and the new front end attenuator settings. This action is

taken automatically by the TR122_SetChannel function.

DCAPI TR122_SaveData(BYTE Format, char *Filename);

This routine saves data for all valid samples in sample memory to the file named. Any existing file is overwritten.

The validity of data is dependant on the last call to TR122_GetTriggerInformation, which should always be called

before this routine is called. The format is text or binary as defined in the header file.

DCAPI TR122_SetHorizontal(DWORD nSPerDiv);

This routine is generally used only when operating the instrument in the oscilloscope mode and displaying data on

the screen DIB. The sample rate is set based on the specified horizontal rate along with certain other related internal

parameters.

DCAPI TR122_SetChannel(BYTE Channel, BYTE AC, BYTE Ohm50, BYTE Range, BYTE Exponent);

This routine allows direct setting of the front end attenuator for the specified channel, 1 or 2. The coupling and

impendence arguments are boolean. The base full scale range is determined by Range as set to

CHANNEL_RANGE_X control values defined in the header file. The exponent is 0, 1, or 2 for the base range

of 100mV, 200mV, or 500mV multiplied by 10

, 10

, or 10

volts per division.

DCAPI TR122_SetupScopeMemory(void);

This routine contains only a call to TR122_SetSampleSegementSize to set the memory geometry as expected by

code related to oscilloscope mode operation.

DDC TR122 User Manual

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