22-06-2012, 04:50 PM
Thermistor Thermometer: LCD version
Thermistor Thermometer.docx (Size: 79.04 KB / Downloads: 30)
Hardware Schematic
The ADC and thermistor circuits are quite the same as the 1st version. The ADC can be LTC1298 or MCP3202. Now with this design, P0 is used to interface LCD bus. SW1 is optional key switch. Since the number of I/O port are not many, we then can replace the 40-pin MCU with 20-pin MCU easily. J2 is available for connecting another sensor. The input range is 0 to +5V.
Software
The main function is the same as 1st version. Now with LCD, the function print_ADC() will use sprintf, to print formatted ASCII string into the buffer. Then the string can be sent to the LCD by function print_LCD. The 0xc0 is the address for 2nd line.