| 摘要 |
PURPOSE:To reduce the amount of microcomputer arithmetic processing to reduce the processing time for temperature data detection by referring to a temperature data conversion table according to an identified resistance type potential divider circuit, and retrieving the temperature data digitized. CONSTITUTION:A microcomputer MC closes either of switches SW1-SW3 to suit the outside air temperature sensed by a temperature sensing portion, digitizes the outputs of a resistance type potential divider circuit using an A/D converter CV, and stores the digitized values in ROM as temperature data Dx1'-Dx3'. The data are determined as being within either of the following temperature measuring ranges: -10-20 deg.C (low range), 20-50 deg.C (medium range), and 50-80 deg.C (high range). From a temperature data conversion table TBA (A)-TBA(C) to be referred to which is selected on the basis of the determined measuring range, either of the data Dx1'-Dx3' that serve as the outputs of the resistance type potential divider circuit are retrieved, and the temperature data corrected into linear form Dx1-Dx3 that correspond to the retrieved data are read. The temperature data Dx1-Dx3 can thus be obtained without performing arithmetic processing using the microcomputer MC. |
