ee3954_fall13_10_adc

17 successive approximation example 43v step 2 bit 6

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Unformatted text preview: 5V D7 = 0 (0XXX XXXX) 0V D7 = Most Significant Bit Result: 1XXX XXXX ADC.17 Successive Approximation Example – 4.3V – Step 2 – Bit 6 (D6) 5V 4.3V D6 = 1 (11XX XXXX) D6 = 0 (10XX XXXX) Threshold = 3.75 0V D7 = Most Significant Bit Result: 11XX XXXX ADC.18 Example Voltage input range: 0V – 5V Number of bits: 8 => 28 = 256 levels (= 255 thresholds) Resolution = 5V / 256 = 0.01953125 V Thresholds at : 0.01953125 V 2x0.01953125 V = 0.0390625 V 3x0.01953125 V = 0.05859375 V … … 4.3V / resolution = 220.16 => 220 = binary value = 1101 1100 ADC.19 ADC As part of the microcontroller … •  Reference Manual: –  Section 21 & 22 (8-bit ADC), –  Section 23 (10-bit ADC) •  Datasheet: –  Section 11 (10-bit ADC) ADC.20 ADC As part of the microcontroller … Timer0 Timer1 Timer2 ADC* Data Bus 8 Comparators Synchronous Serial Port USARTs Other Modules CCPs Parallel Slave Port PORTF LCD Drivers RF0 RF1 RF2 RF3 RF4 RF5 RF6 RF7 PORTG Voltage Reference *or A/D Data EEPROM RG0 RG1 RG2 RG...
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