bx_digital_out
#define BX_DIGITAL_OUT chip->bx_digital_out
chip->px_digital_out = chip->bx_digital_out = 6;
chip->px_digital_out = chip->bx_digital_out = 8;
char bx_digital_out, bx_analog_in, bx_digital_in, bx_num;
return bx_digital_out(chip);