Configuration¶

After an xTDC4 device has been initialized (see Initialization), it must be configured before it can acquire data.

To configure an xTDC4 device:

Get a default set of configuration parameters using xtdc4_get_default_configuration().
Change parameters of xtdc4_configuration according to your specific requirements.
Configure the xTDC4 device using xtdc4_configure().

The following example shows a basic configuration of an already initialized xTDC4 device using the default configuration parameters. A complete coding example can be found on github.com/cronologic-de/xtdc_babel or in Section Code Example.

// get a default set of configuration parameters
xtdc4_configuration config;
status = xtdc4_get_default_configuration(device, &config);
if (status != XTDC4_OK) { /* handle error */ }

// configure the device
status = xtdc4_configure(device, &config);
if (status != XTDC4_OK) { /* handle error */ }

xtdc4_configure¶

int xtdc4_configure(xtdc4_device *device, xtdc4_configuration *config)¶

Configures an xTDC4 device.

Parameters:

device – Pointer to an xTDC4 device.
config – Pointer to an xtdc4_configuration struct used for the configuration.

Returns:

Status code: XTDC4_OK, XTDC4_INVALID_DEVICE, XTDC4_HARDWARE_FAILURE, or XTDC4_INVALID_CONFIG_PARAMETERS.

xtdc4_get_default_configuration¶

int xtdc4_get_default_configuration(xtdc4_device *device, xtdc4_configuration *config)¶

Obtain a default set of configuration parameters.

Parameters:

device – Pointer to an xTDC4 device.
config – Pointer to an xtdc4_configuration struct that will be filled.

Returns:

Status code: XTDC4_OK, XTDC4_INVALID_DEVICE, or XTDC4_CRONO_INVALID_ARGUMENTS.

xtdc4_get_current_configuration¶

int xtdc4_get_current_configuration(xtdc4_device *device, xtdc4_configuration *config)¶

Obtain the current set of configuration parameters of an already configured xTDC4 device.

Parameters:

device – Pointer to a configured xTDC4 device.
config – Pointer to a xtdc4_configuration struct that will be filled.

Returns:

Status code: XTDC4_OK, or XTDC4_INVALID_DEVICE.

xtdc4_configuration¶

struct xtdc4_configuration¶

This struct is used to configure an xTDC4 device using xtdc4_configure().

int size¶: The number of bytes this struct occupies.

int version¶: Version number of this struct. It is increased when the definition of the struct changes.

int tdc_mode¶

Operational mode of the TDC.

Must be equal to the following:

XTDC4_TDC_MODE_GROUPED¶

Operate in grouped mode.

Classical Common-Start operation. See also Grouping and Events.

crono_bool_t start_rising¶: Selects whether the rising or falling edge of the start signal is used to start a group.

double dc_offset[XTDC4_TDC_CHANNEL_COUNT + 1]¶

Set the threshold voltage for the input channels S, A–D.

xtdc4_trigger¶

struct xtdc4_trigger¶

Configure if rising or falling or both edges create a trigger event for xtdc4_tiger_block.

Select which edge(s) trigger an event inside the FPGA.

The xTDC4 can output measurements with a reduced bin size of 5/6 ≈ 833.3 ps for one or both edges of the input signal. Use xtdc4_channel.rising to select which edge is measured with full resolution.

Attention

The edge that is selected for full-resolution measurements must also be enabled for a low-resolution measurement, here.

See Handling of Difficult Hits for more information on hits with varying resolution.

crono_bool_t falling¶: Falling edges will trigger an event.

crono_bool_t rising¶: Rising edges will trigger an event.

xtdc4_tiger_block¶

struct xtdc4_tiger_block¶

This struct configures the Timing Generators [see also Timing Generators (TiGer)].

crono_bool_t enable¶: Activates the TiGer.

Note

To use a TiGer, make sure to also set enable_lemo_output to true.

crono_bool_t negate¶

Inverts the output polarity.

Default is false.

crono_bool_t retrigger¶

Enables re-triggering.

If re-triggering is enabled, the following applies: After an event triggered the TiGer output, another event that is detected before the stop value is reached will extend the TiGer output for a time stop minus start.

crono_bool_t extend¶: Not applicable for the xTDC4.

crono_bool_t enable_lemo_output¶

Enables the LEMO output.

Drive the TiGer signal to the corresponding LEMO connector as an output.

Pulses created by the TiGer are visible at the corresponding input and can be used to get their exact timing.

Attention

The output is DC coupled. Make sure to not connect any devices to the corresponding input, as this may damage the device or the xTDC4.

uint_32_t start¶

Configure the duration when the TiGer output is enabled relative to the trigger.

xtdc4_channel¶

struct xtdc4_channel¶

crono_bool_t enabled¶: Enable the TDC channel.

crono_bool_t rising¶

Select which edge of the signal is used for full-resolution measurements.

For selecting a signal edge for low-resolution measurements, xtdc4_trigger.rising and xtdc4_trigger.falling are used.

Attention

The edge that is select for full-resolution measurements here must also be selected for low-resolution measurements.

See Handling of Difficult Hits for more information on hits with varying resolution.

crono_bool_t cc_enable¶

Enable Delay-Line TDC.

This is set to true by default and should be left unchanged.

crono_bool_t cc_same_edge¶

Sets whether the Delay-Line TDC records the same or the opposite edge as the full-resolution TDC chip.

If the same edge is selected, the Delay-Line TDC acts as a backup if the full-resolution TDC chip misses hits due to FIFO overflows or short input pulses.

If opposite edges are selected, both edges of a pulse can be measured with reasonable resolution.

See Handling of Difficult Hits for more information on hits with varying resolution.

crono_bool_t ths788_disable¶

Disable full-resolution timestamps.

This is set to false by default and should be left unchanged.

uint32_t start¶

Start value for the grouping functionality.

In multiples of xtdc4_param_info.binsize.

See also stop and Grouping and Events.

uint32_t stop¶

Stop value for the grouping functionality.

In multiples of xtdc4_param_info.binsize.

Only hits between start and stop are read out.

The range is 0 ≤ start ≤ stop < 2³⁰.