![NEC V850/SA1 mPD703015 Скачать руководство пользователя страница 303](http://html.mh-extra.com/html/nec/v850-sa1-mpd703015/v850-sa1-mpd703015_preliminary-users-manual_249279303.webp)
CHAPTER 11 A/D CONVERTER
303
11.2 Configuration
The A/D converter consists of the following hardware units.
Table 11-1. Configuration of A/D Converter
Item
Configuration
Analog input
12 channels (ANI0 through ANI11)
Register
Successive approximation register (SAR)
A/D conversion result register (ADCR)
A/D conversion result register H (ADCRH): only high-order 8 bits
can be read
Control register
A/D converter mode register (ADM)
Analog input channel specification register (ADS)
(1) Successive approximation register (SAR)
This register compares the voltage value of the analog input signal with the voltage tap (compare voltage) value
from the series resistor string, and holds the result of the comparison starting from the most significant bit (MSB).
When the comparison result has settled down to the least significant bit (LSB) (i.e., when the A/D conversion has
been completed), the contents of the SAR are transferred to the A/D conversion result register.
(2) A/D conversion result register (ADCR)
Each time a conversion has been completed, the result of the conversion is loaded to this register from the
successive approximation register (SAR). The upper 10 bits of this register holds the result of the A/D
conversion (the lower 6 bits are fixed to 0). This register is read using a 16-bit memory manipulation instruction.
RESET input sets ADCR to 0000H.
When using only upper 8 bits of the result of the A/D conversion, ADCRH is read using an 8-bit memory
manipulation instruction.
RESET input sets ADCRH to 00H.
Caution
When the write operation is performed for the A/D converter mode register (ADM) and the
analog input channel specification register (ADS), the value of ADCR may be undefined. Read
the conversion result after the termination of the conversion operation and before the write
operation for ADM and ADS. If a different timing than above is used, the conversion result may
not be read properly.
(3) Sample & hold circuit
The sample & hold circuit samples each of the analog input signals sequentially sent from the input circuit, and
sends the sample to the voltage comparator. This circuit also holds the sampled analog input signal voltage
during A/D conversion.
(4) Voltage comparator
The voltage comparator compares the analog input signal with the output voltage of the series resistor string.
(5) Series resistor string
The series resistor string is connected between AV
REF
and AV
SS
and generates a voltage for comparison with the
analog input signal.
Содержание V850/SA1 mPD703015
Страница 2: ...2 MEMO ...
Страница 100: ...100 MEMO ...
Страница 144: ...144 MEMO ...
Страница 200: ...200 MEMO ...
Страница 328: ...328 MEMO ...
Страница 356: ...356 MEMO ...
Страница 358: ...358 MEMO ...
Страница 368: ...368 MEMO ...
Страница 374: ...374 MEMO ...
Страница 382: ...382 MEMO ...