Hi All,
I'm working on a project that uses the Beagleboard (OMAP3530) for high speed data acquisition. The data is sampled quickly using either a McSPI interface or through a custom parallel interface using the expansion interface on the Beagleboard. In both cases DMA is used to write directly to memory. The high level problem is that we appear to be missing DMA transactions (up to 2) when a DMA packet is written, i.e every 4096 bytes.
There are some comments either in an Errata to datasheet or technical reference manual that dscuss missed DMA events. I'm wondering if this is how the hardware issues would manifest themselves at the operating system level and I'm hoping for some advice on how to rectify the situation, i.e. do we need to re-write the DMA drivers to work around the issue?
JT
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More background:
We've based the system on the Arago build of Linux.
The sample sizes we've been working with are between 10 to 50Mbytes but can be smaller or much larger.
The serial data rates are less then 20Mbps.
The parallel word capture rate is approximately 5MSPS.
The DMA packet size is 4032 bytes plus 64 bytes of administrative information.