Ultrasonic Distance Measurement HT45F39 Characteristics Operating Voltage : 5.0V Measurement range : 55cm ~ 340cm Precision : 0.3cm Ultrasonic sensor : 40kHz Auto-Envelope Processor (AEP) for input signal processing External NTC to Distance Temperature − adjust sound velocity Application Areas Block Diagram HT45F39 VDD 5V Shunt Regulator VSS PA4/AN4 HT8 MCU Core IAP/ICP LVR INT LIRC/WDT Timebase ROM 2K x 16 RAM 128 x 8 HIRC OSC. PB1 GPIO PB2 PA0/TP0/AN0/SDAT CTM0 HSBCU S1 PB0 PA5/SCFO/AN5 PA3/TCK0/AN3 PA1/AN1 GPIO AEP VREF 1.25 CTM1 OP1O HS ADC PA6/TCK1/AN6 - - + + VCM … S2 PA7/AN7 Application Circuit 40KHz/58KHz Band Pass SCF 5V - HSBCU + PA2/TP1/AN2//SCLK OP1N