UPD78F0138 NEC, UPD78F0138 Datasheet - Page 264

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

264
The setting methods are described below.
• When used as A/D conversion operation
<Change the channel>
<Complete A/D conversion>
• When used as power-fail function
<Change the channel>
<Complete A/D conversion>
<1> Set bit 0 (ADCE) of the A/D converter mode register (ADM) to 1.
<2> Select the channel and conversion time using bits 2 to 0 (ADS2 to ADS0) of the analog input channel
<3> Set bit 7 (ADCS) of ADM to 1.
<4> An interrupt request signal (INTAD) is generated.
<5> Transfer the A/D conversion data to the A/D conversion result register (ADCR).
<6> Change the channel using bits 2 to 0 (ADS2 to ADS0) of ADS.
<7> An interrupt request signal (INTAD) is generated.
<8> Transfer the A/D conversion data to the A/D conversion result register (ADCR).
<9> Clear ADCS to 0.
<10> Clear ADCE to 0.
Cautions 1. Make sure the period of <1> to <3> is 14
<1> Set bit 7 (PFEN) of the power-fail comparison mode register (PFM).
<2> Set power-fail comparison condition using bit 6 (PFCM) of PFM.
<3> Set bit 0 (ADCE) of the A/D converter mode register (ADM) to 1.
<4> Select the channel and conversion time using bits 2 to 0 (ADS2 to ADS0) of the analog input channel
<5> Set a threshold value to the power-fail comparison threshold register (PFT).
<6> Set bit 7 (ADCS) of ADM to 1.
<7> Transfer the A/D conversion data to the A/D conversion result register (ADCR).
<8> The higher 8 bits of ADCR and PFT are compared and an interrupt request signal (INTAD) is generated
<9> Change the channel using bits 2 to 0 (ADS2 to ADS0) of ADS.
<10> Transfer the A/D conversion data to the A/D conversion result register (ADCR).
<11> The higher 8 bits of ADCR and the power-fail comparison threshold register (PFT) are compared and an
<12> Clear ADCS to 0.
<13> Clear ADCE to 0.
Cautions 1. Make sure the period of <3> to <6> is 14
specification register (ADS) and bits 5 to 3 (FR2 to FR0) of ADM.
specification register (ADS) and bits 5 to 3 (FR2 to FR0) of ADM.
if the conditions match.
interrupt request signal (INTAD) is generated if the conditions match.
2. It is no problem if the order of <1> and <2> is reversed.
3. <1> can be omitted. However, do not use the first conversion result after <3> in this
4. The period from <4> to <7> differs from the conversion time set using bits 5 to 3 (FR2 to
2. It is no problem if the order of <3>, <4>, and <5> is changed.
3. <3> must not be omitted if the power-fail function is used.
4. The period from <7> to <11> differs from the conversion time set using bits 5 to 3 (FR2 to
case.
FR0) of ADM. The period from <6> to <7> is the conversion time set using FR2 to FR0.
FR0) of ADM. The period from <9> to <11> is the conversion time set using FR2 to FR0.
CHAPTER 12 A/D CONVERTER
User’s Manual U16228EJ2V0UD
µ
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s or more.
s or more.