implement PWT buzzer driver The piece implemented here is the low-level driver component; there will also be a higher-level buzzer melody player service, to be implemented in RiViera land, that will be the sole caller of PWT API functions provided by the present driver.

/*
 * This header file is a FreeCalypso addition: it defines the functional
 * interface to the PWT buzzer driver.
 */

void PWT_block_on(void);
void PWT_block_off(void);
void PWT_play_tone(SYS_UWORD8 note, SYS_UWORD8 volume);
void PWT_stop_tone(void);