ADCON:MOV DPTR, # 0F0FFH gated ADC0809 channel 0
MOV A, # 00H channel 0 = 00H channel 1 = 0 1h- channel 7 = 07H.
MOVX @DPTR,A; Start analog-to-digital conversion
Here: JNB P3.3, here; Judge whether the data conversion is completed, and wait if it is not.
MOVX A,@ DPTR; Read the converted data
MOV 20H,A; The voltage value on the thermistor at the current temperature read from ADC0809 is stored in units of 20H.
RET