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10-Bit A/D Converter

10-Bit A/D Converter. ADC 轉換 / 取樣動作. ADC_FORMAT_INTG. ADCON1bits.FORM 11 = 有號小數 10 = 無號小數 01 = 有號整數 00 = 整數. ADC_CLK_AUTO. ADCON1bits.SSRC 111 = 自動轉換 . . . 000 = 手動轉換 ( 清除 SAMP 後開始轉換 ). 兩種取樣方式. ADC_SAMPLE_SIMULTANEOUS. ADCON1bits.SIMSAM 1 = 所有通道同時取樣 0 = 各個通道個別取樣.

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10-Bit A/D Converter

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  1. 10-Bit A/D Converter

  2. ADC 轉換/取樣動作

  3. ADC_FORMAT_INTG • ADCON1bits.FORM • 11 = 有號小數 • 10 = 無號小數 • 01 = 有號整數 • 00 = 整數

  4. ADC_CLK_AUTO • ADCON1bits.SSRC • 111 = 自動轉換 • . • . • . • 000 = 手動轉換 (清除SAMP後開始轉換)

  5. 兩種取樣方式

  6. ADC_SAMPLE_SIMULTANEOUS • ADCON1bits.SIMSAM • 1 = 所有通道同時取樣 • 0 = 各個通道個別取樣

  7. ADC_AUTO_SAMPLING_OFF • ADCON1bits.ASAM • 1 = 轉換完後立即自動取樣 • 0 = 手動取樣，SAMP設為1開始取樣

  8. 10-Bit ADC BLOCK DIAGRAM

  9. 輸入多工器 • AD轉換器有兩組多工器(A與B)可選擇

  10. ADC_ALT_INPUT_OFF • ADCON2bits.ALTS • 1 = 交互使用A, B 多工器 • 0 = 只用A多工器

  11. ADC_CONVERT_CH_0A • ADCON2bits.CHPS • 1x = 轉換CH0, CHA, CHB and CHC • 01 = 轉換CH0 and CHA • 00 = 轉換CH0

  12. ADC_SAMPLES_PER_INT_1 • ADCON2bits.SMPI • 16 = 每完成16次取樣的轉換，產生1中斷 • 15 = 每完成15次取樣的轉換，產生1中斷 • . • . • . • 1 = 每完成1次取樣的轉換，產生1中斷 • 範例雖然是雙通道，但為同時取樣，所以設定為1

  13. Channel • ADC_CH0_POS_SAMPLEA_AN6 • CH0正端經A多工器接到AN6 • ADC_CH0_NEG_SAMPLEA_NVREF • CH0負端經A多工器接到VREF- (=Vss) • ADC_CHX_POS_SAMPLEA_AN0AN1AN2 • 正端經多工器A，CHA接AN0，CHB接AN1… • ADC_CHX_NEG_SAMPLEA_NVREF • CHA, CHB與CHC負端通通接到VREF-

  14. 10-Bit ADC BLOCK DIAGRAM

  15. 輸入多工器 • AD轉換器有兩組多工器(A與B)可選擇 • Output = [(VA+ - VA-)- VREF-] / (VREF+ - VREF-) * 1024 - 1

  16. BusyADC10() • ADCON1bits.DONE • 1 = 轉換完成 • 0 = 開始轉換時清除為0，也可手動清除

  17. 手動取樣自動轉換流程 同時取樣 CH0轉換 CHA轉換 同時取樣 SAMP DONE 手動設定SAMP=1 開始取樣 自動轉換 自動清除SAMP&DONE 轉換完成 自動設定DONE

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