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4 Packet Format

4.0.2 Output Structure ndigo packet

unsigned char channel

0 to 3 for the ADC input channels, 4 for the TDC, 5 for the timestamp channel.

unsigned char card

Identiﬁes the source card in case there are multiple boards present. Defaults to 0 if no value is

assigned to the parameter board id in Structure ndigo init parameters or set via

int ndigo set board id(ndigo device *device, int board id).

unsigned char type

For the ADC channels this is set to 1 to signify 16 bit signed data.

For the TDC channel it is set to 8 to signify 64 bit unsigned data.

If the type ﬁeld is 128 or greater then there is no data present, even if length is not 0. In this

cases the length ﬁeld may contain other data.

Type Length Field Description

1 Number of payload words 16 bit signed samples from one of the ADCs

8 Number of payload words 64 Bit unsigned TDC Data, only for internal processing

128 Bit pattern of trigger sources Whenever at least one of the sources that is enabled for the

timestamp channel triggers, one of these packets is generated.

The length ﬁeld contains the triggers that are active when this

packet was created.

unsigned char ﬂags

If the bit with weight 1 is set, the packet was truncated because the internal FIFO was full.

If the bit with weight 2 is set, there are lost triggers immediately preceding this packet due

to insuﬃcient DMA buﬀers.

If the bit with weight 4 is set, the packet contains ADC sample overﬂows.

If the bit with weight 8 is set, there are lost triggers immediately preceding this packet due

to insuﬃcient buﬀers.

unsigned int length

1 2 ... 42 43 44 45 46 47 48 49 50 51 52 ... 56 57

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