Rainbow-electronics ATtiny26L Manuel d'utilisateur télécharger pdf (Page 83)

ATtiny26(L)

1477B–AVR–04/02

Figure 51. Differential Measurement Range

Example:

ADMUX = 0xEB (ADC0 - ADC1, 20x gain, 2.56V reference, left adjusted result)

Voltage on ADC0 is 400 mV, voltage on ADC1 is 300 mV.

ADCR = 1024 * 20 * (400 - 300) / 2560 = 800 = 0x320

ADCL will thus read 0x00, and ADCH will read 0xC8. Writing zero to ADLAR right

adjusts the result: ADCL = 0x20, ADCH = 0x03.

Table 35. Correlation Between Input Voltage and Output Codes

ADCn

Read code Corresponding decimal value

ADCm

+ V

REF

/GAIN 0x3FF 1023

ADCm

+ 0.999 V

REF

/GAIN 0x3FF 1023

ADCm

+ 0.998 V

REF

/GAIN 0x3FE 1022

... ... ...

ADCm

+ 0.001 V

REF

/GAIN 0x001 1

ADCm

0x000 0

Output Code

0x3FF

0x000

REF

/GAIN

Differential Input

Voltage (Volts)

1 2 ... 78 79 80 81 82 83 84 85 86 87 88 ... 150 151

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Rainbow-electronics ATtiny26L Manuel d'utilisateur Page 83