CompuScope SDK Manua.. - Egmont Instruments

as long the group number is less than or equal to the number of acquired groups. When the passed group
number is not equal to the return value, this indicates that the passed group number is outside the rage of
valid captured groups.
The recommended way of downloading all the groups in a Multiple Record capture is shown below:
gage_get_driver_info (&gdi);
tbs = 1000000000 / sample_rate; /* tbs is time between samples in nanoseconds. The correct value must
be passed to address calculation routines for correct operation */
group = 1;
while (group == gage_calculate_mr_addresses (group, gdi.board_type, gdi.depth,
gdi.max_available_memory, chan, gdi.mode, tbs, &trig, &start, &end) {
}
size = end - trig +1;
offset = gage_transfer_buffer_3 (trig, GAGE_CHAN_A, buffer, size);
display_data(offset); /*User-supplied routine that displays buffer, beginning at offset*/
group++;
The above sample code assumes that the buffer has already been allocated. The capture was in dual
channel mode and only data from channel A is being transferred from the CompuScope acquisition
memory to PC memory.
Note that size was calculated to be end – trig +1. In Multiple Record mode there is no pre-trigger data, so
the end address will always be greater than the trigger address.
The above method is convenient if you don't know the total number of groups that have been captured
because of the inter-record padding. If you've aborted the capture after a predetermined number of groups,
or the driver routine gage_multiple_record_acquisitions is available for your CompuScope board, you
can use a for loop to read only the number of groups of interest.
Embedded Enhanced Trigger Bits
A factory option available on most CompuScope boards with Multiple Record is Embedded Enhanced
Trigger Bits. Due to the architecture of the CompuScope Multiple Record hardware, there is some
uncertainty inherent in the trigger address because the least significant bits of this address are not
maintained. The Embedded ETB option embeds the least significant bits of the trigger address (the ETBs)
in an early sample of each Multiple Record group. After download, these embedded ETBs can be
recovered and then used to resolve the trigger address uncertainty.
On CompuScopes with the Embedded ETB functionality, the trigger address returned by
gage_calculate_mr_addresses will point to the sample that that contains the enhanced trigger bits (ETBs).
This sample must be downloaded using the gage_mem_read_master function as illustrated below:
data = gage_mem_read_master(trig);
In a Master/Slave CompuScope system, the ETBs for records from all CompuScopes in the system (Master
and Slaves) must be downloaded from the Master CompuScope. Using the gage_mem_read_master
function, as illustrated above, ensures that the ETBs are always downloaded from the Master CompuScope.
The embedded ETBs are used to adjust the trigger address using the gage_calculate_mra_addresses
function. The prototype of this function is shown below:
int32 gage_calculate_mra_addresses (int16 board_type, uInt16 board_version, int16 chan, int16
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