Datasheet

78K0/Kx2-L CHAPTER 12 A/D CONVERTER
R01UH0028EJ0400 Rev.4.00 404
Sep 27, 2010
(8) Successive approximation register (SAR)
The SAR register is a 10-bit register that sets a result compared by the A/D voltage comparator, 1 bit at a time starting
from the most significant bit (MSB).
If data is set in the SAR register all the way to the least significant bit (LSB) (end of A/D conversion), the contents of
the SAR register (conversion results) are held in the A/D conversion result register (ADCR, ADCRH).
(9) 10-bit A/D conversion result register (ADCR)
The A/D conversion result is loaded from the successive approximation register to this register each time A/D
conversion is completed, and the ADCR register holds the A/D conversion result in its lower 10 bits (the higher 6 bits
are fixed to 0).
(10) 8-bit A/D conversion result register L (ADCRL)
The A/D conversion result is loaded from the successive approximation register to this register each time A/D
conversion is completed, and the ADCRL register stores the lower 8 bits of the A/D conversion result.
(11) 8-bit A/D conversion result register H (ADCRH)
The A/D conversion result is loaded from the successive approximation register to this register each time A/D
conversion is completed, and the ADCRH register stores the higher 8 bits of the A/D conversion result.
Caution When data is read from ADCR, ADCRL, and ADCRH, a wait cycle is generated. Do not read data
from ADCR, ADCRL, and ADCRH when the peripheral hardware clock (f
PRS) is stopped. For details,
refer to CHAPTER 31 CAUTIONS FOR WAIT.
(12) Controller
This circuit controls the conversion time of an input analog signal that is to be converted into a digital signal, as well
as starting and stopping of the conversion operation. When all the specified A/D conversion has been completed, this
controller generates an A/D conversion end interrupt request signal (INTAD).
(13) AV
REF pin
This pin inputs an analog power/reference voltage to the A/D converter. Make this pin the same potential as the V
DD
pin when port 2 is used as a digital port.
The signal input to ANI0 to ANI10 is converted into a digital signal, based on the voltage applied across AV
REF and
AV
SS.
(14) AV
SS pin (78K0/KB2-L and 78K0/KC2-L only)
This is the ground potential pin of the A/D converter. Always use this pin at the same potential as that of the V
SS pin
even when the A/D converter is not used.
(15) V
SS pin
This is the ground potential pin. In the 78K0/KY2-L and 78K0/KA2-L, V
SS functions alternately as the ground potential
of the A/D converter. Be sure to connect V
SS to a stabilized GND (= 0 V).