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Diff: vga640x400.c
- Revision:
- 3:ab761080df98
- Parent:
- 2:70daa29e01bd
- Child:
- 4:3f0bd68a4dda
--- a/vga640x400.c Sun Jul 24 16:34:25 2011 +0000 +++ b/vga640x400.c Wed Aug 10 11:24:28 2011 +0000 @@ -35,9 +35,15 @@ // ----------------------------------------------------------------------------------- -unsigned char text_buffer[80*25]; -unsigned char *font; - +unsigned char text_buffer[80*25]; ///< 80x25 screen buffer, i.e. 25 lines of 80 characters. +unsigned char *font; ///< Pointer to the user supplied font. + ///< Each character is 8 pixels wide and 16 pixels high. + ///< The font consists of 16 groups of 256 bytes. + ///< i.e. 256 times the first byte of each character, then + ///< 256 times second byte of each character, and so on. + ///< This differs from the most common way bitmap fonts are + ///< ordered, so you have to preprocess your font data first. + static unsigned line_counter; static unsigned char scanline0[100], scanline1[100]; // 100*8=800 color clocks static unsigned char *curline = scanline1+20; @@ -251,6 +257,13 @@ // ----------------------------------------------------------------------------------- +/** Initialize the VGA signal + * + * This function should be the very first thing you call, before doing anything else. + * It turns off all peripherals, sets the main clock to 100MHz (instead of the 96MHz default of the mbed) + * and switches on PWM, I2S and DMA. + */ + void init_vga(void) { fl_power_off_all_peripherals();