DATA_REG_B
bus_space_write_1(bst, bsh, DATA_REG_B, (length + 6) & 0xff);
bus_space_write_1(bst, bsh, DATA_REG_B, ((length + 6) >> 8) & 0xff);
bus_space_write_1(bst, bsh, DATA_REG_B,
bus_space_write_1(bst, bsh, DATA_REG_B, 0);
*data = bus_space_read_1(bst, bsh, DATA_REG_B);