Advices for a new project

Oct 14, 2010 1 Replies

We have an Acquisition module which gives 12 channel ECG signals from



12 leads. We are planning to use ADSP BF 527 to acquire ECG samples from the acquisition module and transfer the samples as packets using USB 1.1 of blackfin to a host processor running an embedded OS.


I wish to get some information to get a start.


The basic Question is What type of USB transfer should i use for transferring ECG samples? Bulk, Isochronous or Interrupt?


What type of buffers should i use to store the acquired data? Is it 1D buffer or 2D buffer or Circular Buffer.


What type of dataflow method should i use? Is it Chained with or without loopback.


I also need to transfer the software/firmware version from the Blackfin to the host ? For that which transfer type should i use?



It will be really helpful if someone can shed some light on these queries of mine.


Thanks in advance


ECG must be isolated from the PC I guess ? Where do you put the isolation barrier ?

Interrupt is for things like keyboards etc. Isochronous is for things like soundcard where a packet not on time is as good as a lost packet. Bulk is the rest.

I guess for ECG data you should use Bulk. If the PC isn't so snappy and stops polling the device for like 10 milliseconds, using isochronous you'll lose the data, using bulk it'll be buffered in your device and pulled later. Timestamp your data at the source, and you're fine.

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