The little TFT LCD card from Adafruit I'm experimenting with (see other post) has a micro SD card adapter on it and one of Adafruit's sample Arduino apps for the device is to read a bitmap image from the SD card and paint it on the TFT...and Hurrah, I have got it working on the Maple, using CodeRage's SdFat library. Adafruit use their own upgraded version of the Arduino FAT library so it wasn't the easiest port in the world. For some reason they were passing a File object amongst functions, rather than a reference, and something I didn't notice when I replaced all File references with SdFile instead. The file load was failing with a bitmap error because only the throwaway object on the stack was getting its cur_position updated. Oh well! They are all easy once you've found them, aren't they!
Interesting aside. This is a 62Kbyte image file. With the SPI clock set at 250KHz, the load and draw process took 3203 ms. Once I got it working, I kept increasing SPI hardware clock speed until the SD card failed, and that was at 9MHz. It runs reliably at 4.5MHz and the load and draw process takes 583 ms, almost 6 times quicker.
...anyway kudos to CodeRage for his great work...
