We are starting a new project for developing an Electrocardiograph. We have an
Acquisition module which gives 12 channel information 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
Shafi
Seeking advices for starting a project.
Started by ●October 12, 2010
Reply by ●October 13, 20102010-10-13
> We are starting a new project for developing an
Electrocardiograph. We
> have an Acquisition module which gives 12 channel information 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?
I just heard a talk about this yesterday. You want interrupt. You can
still send up to 3k per packet, but you only have to send it when the host
wants it.
> What type of buffers should i use to store the acquired data?
> Is it 1D buffer or 2D buffer or Circular Buffer.
Your choice. I'd use circular but 2d makes a lot of sense too.
> 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?
One thing the speaker told us was to pick something for which a driver
already exists. You can save yourself a lot of effort if you pick one
thing like HID. Make everything look the same to the driver level,
construct the packets so they make sense to you at the application layer.
> It will be really helpful if someone can shed some light on these queries
> of mine.
USB is insanely complex. If you can find a software package that does
most of what you need and you don't need to build custom drivers, you will
get the job done a lot faster. There are a lot of companies that
specialize in USB, I suspect a web search will find a few that know how to
do it with blackfins.
I know enough now to know I don't want to do it :-)
Patience, persistence, truth,
Dr. mike
> have an Acquisition module which gives 12 channel information 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?
I just heard a talk about this yesterday. You want interrupt. You can
still send up to 3k per packet, but you only have to send it when the host
wants it.
> What type of buffers should i use to store the acquired data?
> Is it 1D buffer or 2D buffer or Circular Buffer.
Your choice. I'd use circular but 2d makes a lot of sense too.
> 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?
One thing the speaker told us was to pick something for which a driver
already exists. You can save yourself a lot of effort if you pick one
thing like HID. Make everything look the same to the driver level,
construct the packets so they make sense to you at the application layer.
> It will be really helpful if someone can shed some light on these queries
> of mine.
USB is insanely complex. If you can find a software package that does
most of what you need and you don't need to build custom drivers, you will
get the job done a lot faster. There are a lot of companies that
specialize in USB, I suspect a web search will find a few that know how to
do it with blackfins.
I know enough now to know I don't want to do it :-)
Patience, persistence, truth,
Dr. mike
