Prototype receiver circuit based on AM26LV32 chip: The MagJack - a Bel Stewart SI-52008-F has datasheet here: http://www.farnell.com/datasheets/1731561.pdf The IC cleans up the edges of the incoming signals. With some level-shifting and AC coupling, the signals are OK to pass into an SPDIF receiver.

Here’s a graph showing the write performance to a Sandisk Class 10 memory card. The reason for the sharp dips in performance, are that the FAT filing system has to go off and allocate a new cluster every N writes. For example 512 byte sectors, 32Kbyte clusters, means a new cluster is needed every 64 writes. Another factor on the XMOS board is whether the code is running in ‘debug’ or ‘release’ mode.

Being able to read/write information from an SD card is probably the easiest way to get large amounts of non-volatile storage into an embedded project. I’m using XMOS StartKit, with the code from here The card reader is a part from Wurth Elektronik, Farnell / CPC part number CN18143 available here. The data and clock lines have 120 ohm series resistors, as this can help to absorb transmission-line reflections on the connecting wires (even though they are fairly short).

I recently got one of these great little digital scopes. It has a few serial bus decoding packages (on a try-before-buy basis). You get 36 hours to play with them. Unfortunately they don’t include I2S bus decoding. I2S is a bus standard commonly used for transferring digital audio around, for example between ADCs and DACs. No matter! You can capture and export full-resolution traces of signals via a USB memory stick.