For each display model, the demonstration program will attempt to read a default file. The default file must be available on the SD Card or the NHDev LCD Development Board’s program will error and halt. The default file is always signified by a 0 (zero) immediately before the .BMP or .TXT file format extension. After reading and displaying the default file, the SEL button can be pressed to write the next file to the target display. The next file is determined by incrementing the number or letter immediately before the .BMP or .TXT file extension: 0 through 9, then A through Z. If the next file does not exist, or after file ‘Z’, the default file ‘0’ will be displayed again.