Re: Re. installation of EPICS for beam position measurement using Raspberrypi

[Eric Norum <eric@norum.ca>]

What analog signal conditioning are you using to get the pickup electrode signals converted to the range that could be measured with a 2 Msample/second ADC?  Typical modern BPMs use ADCs with sampling frequencies in the 100 Msample/second and up range and an FPGA to perform the signal processing and beam position computation.

On Feb 9, 2016, at 9:47 PM, vivek singh <viveksingh74155@gmail.com> wrote:

I want to use EPICS in my raspberry pi for beam position measurement.  I will be using 4 16-bit ADC's for digitizing the output of the pickup electrodes. The ADC's support serial and parallel interfaces.  Since the Pi does not have that many GPIOs, I will be using Serial Interface to get the data.  I have a few questions regarding that.

1. The ADC (AD7622) supports 2MSPS.  I wrote a python code to toggle a GPIO pin on a loop after some calculations and the maximum switching frequency I could observe in the

    Oscilloscope was 500kHz.  Is that the maximum speed I can achieve using PI ?

2. The Pi has a dedicated SPI interface, so what is the maximum speed that can be achieved using it ?

Another query I had, was regarding multicore processing capability of the Pi.  

3. Is it possible to control individual cores, so that they can each perform one task that I assign to them, at their maximum capacity ?

Any other suggestions you have regarding this setup would be very helpful.

-- 
Eric Norum
eric@norum.ca