PREC 14 VCON c10 max809 U2 UI OSCI/CLKIN 10 OSC2/CLKOUT CLK VDD MCLR/VPP/THV RCO/TIOSO/TICKI 12 RST VDD VCON RAO/ANO RCI/TIOSI/CCP2 RAI/ANI RC2/CCPI 13 RA2/AN2/VREF- RC3/SCK/SCL 14 55 VCC 5 RA3/AN3/VREF+ RC4/SDI/SDA 16 OE UB RA4/TOCKI RC5/SDO RC6/TX/CK 17 T 21 RA5/AN4/SS WVs WB RBO/INT RC7/RX/DT 18 GND GND 22 RBI 26 RB5 23 SM2001 RB2 RB6/PGC 27 24 25 RB3/PGM RB7/PGD 28 RB4 PIC16F873 Q1 + C1 R5 3 2 1 4 11 U1A VCC 5 6 7 U1B 10 9 8 U1C 12 13 14 U1D R2 R3 VCC C2 R4 D1 VCC VCC R1 PREC VCON CLK RST CS CK DA OE INT WVS GND GND WB VB UB WT VT UT VDD VDD U1 SM2001 RA0/AN0 2 RA1/AN1 3 RA2/AN2/VREF- 4 RA3/AN3/VREF+ 5 RA4/T0CKI 6 RA5/AN4/SS 7 RB0/INT 21 RB1 22 RB2 23 RB3/PGM 24 RB4 25 RB5 26 RB6/PGC 27 RB7/PGD 28 RC0/T1OSO/T1CKI 11 RC1/T1OSI/CCP2 12 RC2/CCP1 13 RC3/SCK/SCL 14 RC4/SDI/SDA 15 RC5/SDO 16 RC6/TX/CK 17 RC7/RX/DT 18 MCLR/VPP/THV 1 OSC1/CLKIN 9 OSC2/CLKOUT 10 U2 PIC16F873 C10 Y1 C11 1 2 3 max809 VCC VCON VCC VCC