HOLTEK HT49RV9/HT49CV9 A/D+VFD Type 8-Bit microcontroller Manual User Manual This document introduces the features and characteristics of the HT49RV9/HT49CV9 A/D+VFD 8-bit microcontroller by Holtek, including the working voltage range, number of I/O ports, timer/counter functions, VFD driver, memory capacity, etc.