GTP_DATA_ON
data = bit ? GTP_DATA_ON : GTP_DATA_OFF;
bus_space_write_1(iot, ioh, off, GTP_WREN_ON | GTP_DATA_ON | GTP_CLCK_OFF);
GTP_DATA_ON | GTP_WREN_OFF | GTP_CLCK_OFF);
GTP_DATA_ON | GTP_WREN_OFF | GTP_CLCK_ON);
#define GTP_READ_CLOCK_LOW (GTP_WREN_OFF | GTP_DATA_ON | GTP_CLCK_OFF)
#define GTP_READ_CLOCK_HIGH (GTP_WREN_OFF | GTP_DATA_ON | GTP_CLCK_ON)