HiTechnic Prototype board constants

HTPROTO_REG_A0 HTPROTO_REG_A1 HTPROTO_REG_A2 HTPROTO_REG_A3 HTPROTO_REG_A4 HTPROTO_REG_DCTRL HTPROTO_REG_DIN HTPROTO_REG_DOUT HTPROTO_REG_SRATE

#define HTPROTO_REG_DCTRL   0x4E Prototype board digital pin control register (6 bits)