Grifo Kernel

Features

• Separate kernel and application binaries
• Simple API for application program in: grifo.h
• Fixed ABI for separate kernel/application updates
• Event queue mechanism with option for low power standby while waiting for the next event, and a callback to capture the timeout (allows for saving unsaved data before power off)
• Text output to LCD
• File/directory handling for SD card
• Watchdog timer auto power off
• Application main must be the first code in the first object linked

Boot sequence

• Hardware initialisation
• Run the command: init.app auto-boot grifo-kernel
• init.app runs
• All files are closed on return
• One of three possible actions occurs depending on the value returned to the kernel:
  • Power off
  • Reboot - equivalent to power on reset
  • Run: init.app restart grifo-kernel

Initial application: init.app

• Reads a configuration file: init.ini
• example line: hello.ico : hello.app some test arguments
• if auto-boot was present the it unconditionally runs the first program
• if not the first 9 items are displayed as a graphic menu

Program code from examples/hello

This displays a message on the LCD and on the console serial port, then displays the command line arguments provided by init.app.

#include <grifo.h>
int main(int argc, char *argv[])
{
	lcd_clear(LCD_WHITE);
	lcd_printf("Hello LCD world\n");
	debug_printf("Hello serial world\n");
	size_t i;
	for (i = 0; i < argc; ++i) {
		lcd_printf("argv[%d] = '%s'\n", i, argv[i]);
		debug_printf("argv[%d] = '%s'\n", i, argv[i]);
	}
	delay_us(1000000);
	return EXIT_RESTART_INIT;
}