How can I make my own acquisition software ? details

cchristoforos · Post by **cchristoforos** » Fri Nov 05, 2004 8:50 pm

Hi

In the FAQ i found http://www.biosemi.com/faq/make_own_acq ... ftware.htm which indicates the format of the return channels. So according to that document after the aquisition is initiated each sample somepose to contain 258 32-bit values that correspond to the 256 channels (a start and a status bit.

My question is where are the Ex1 to ex8 channels then? is there a different initialization for the aquisition to include those channels.

Any details or references are greatly appreciated.

Thanks
Christoforos

Post by **Coen** » Sat Nov 06, 2004 12:27 am

The EX1-8 ("touchproof") electrodes are connected to channels 232 to 239 (234th to 241th incoming 32-bit word). The last 16 channels (240-256) are reserved for the additional sensors.

The above is valid for speedmodes 0 and 4. On speedmodes 1-3, the EX and sensor channels are not sampled. On speedmodes 5-7, the EX and sensor channels are on the last 24 channels.

Best regards, Coen (BioSemi)

guanja · Post by **guanja** » Wed Oct 17, 2007 11:11 am

Hi，Coen，

The above answering are valid up to now?
The amount of total channels seems to be increased to 282(256+24). In this config where the EX1-8 in coming data flow in a burst transfer?

In a 64K burst transfer to a 32M ring buffer, in what sequence of the coming data ?
is this right?(Ex.: speed mode 4)
syn(4bytes)status(4bytes)channel1(4bytes)channel2(4bytes)...
channel256(4bytes)EX1(4bytes)...EX8(4bytes)other16channels(even not exist)

Post by **Coen** » Wed Oct 17, 2007 2:32 pm

The above is valid for our Mk1 systems (delivered until August 2005), the current Mk2 systems do indeed have extra channels. Meanwhile, the FAQ has been updated, and the figures for both Mk1 and Mk2 are listed, see http://www.biosemi.com/faq/make_own_acq ... ftware.htm). To check whether your system is a Mk1 or Mk2, please read viewtopic.php?t=270 .

The 282 channels in Mk2 speedmode 4 are divided as follows:

sync, trigger, chan 1-256, EX1-EX8, sensors (1+1+256+8+16)

In higher speedmodes, the block of 256 is reduced to respectively 128, 64 and 32, with the rest of the channels left unchanged.

Best regards, Coen (BioSemi)