UPD78F9418AGK-9EU Renesas Electronics America, UPD78F9418AGK-9EU Datasheet - Page 160

• Manufacturer Part Number: UPD78F9418AGK-9EU
• Manufacturer: Renesas Electronics America

Specifications of UPD78F9418AGK-9EU

• Lead Free Status / Rohs Status: Supplier Unconfirmed

11.4 Operation of 10-Bit A/D Converter
11.4.1 Basic operation of 10-bit A/D converter
158
<1> Select a channel for A/D conversion, using A/D input selection register 0 (ADS0).
<2> The voltage supplied to the selected analog input channel is sampled using the sample & hold circuit.
<3> After sampling continues for a certain period of time, the sample & hold circuit is put on hold to keep the input
<4> Bit 9 of the successive approximation register (SAR) is set. The series resistor string voltage tap at the tap
<5> The series resistor string tap voltage is compared with the analog input voltage using the voltage comparator.
<6> Bit 8 of the SAR is set automatically, and comparison shifts to the next stage. The next voltage tap of the
<7> Comparison is repeated until bit 0 of the SAR is reached.
<8> When comparison is completed for all of the 10 bits, a significant digital result is left in the SAR. This value is
The tap voltage is compared with the analog input voltage. Bit 8 is set or reset according to the result of
comparison.
Cautions 1. The first A/D conversion value immediately following the start of A/D conversion may be
analog voltage until A/D conversion is completed.
selector is set to half of AV
If the analog input voltage is higher than half of AV
half of AV
series resistor string is selected according to bit 9, which reflects the previous comparison result, as follows:
sent to and latched in A/D conversion result register 0 (ADCR0). At the same time, it is possible to generate
an A/D conversion end interrupt request (INTAD0).
Bit 9 = 1: Three quarters of AV
Bit 9 = 0: One quarter of AV
Analog input voltage
Analog input voltage < tap voltage: Bit 8 = 0
REF
2. When the A/D converter enters the standby mode, it stops operating.
, the MSB is reset.
undefined.
CHAPTER 11 10-BIT A/D CONVERTER ( PD789417A SUBSERIES)
tap voltage: Bit 8 = 1
REF
.
REF
REF
User’s Manual U13952EJ3V1UD
REF
, the MSB of the SAR remains set. If it is lower than