mc68hc05jb4p Freescale Semiconductor, Inc, mc68hc05jb4p Datasheet - Page 100

• Manufacturer Part Number: mc68hc05jb4p
• Description: Mc68hc705jb4 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

GENERAL RELEASE SPECIFICATION
11.1
ADC OPERATION
As shown in Figure 11-1, the ADC consists of an analog multiplexer, an 8-bit digi-
tal to analog capacitor array, a comparator and a successive approximation regis-
ter (SAR).
There are ten options that can be selected by the multiplexer; the AD0 to AD5
input pins, V
bits in the ADC Status and Control Register. AD0 to AD5 are input points for ADC
conversion operations; the others are reference points which can be used for test
purposes. The converter uses V
age equal to or greater than V
than V
must not be exceeded. Each analog input source should use V
voltage and should be referenced to V
tain full accuracy of the ADC, the following should be noted:
The ADC reference inputs (V
to analog converter. Control logic drives this D/A converter and the analog output
is successively compared with the selected analog input sampled at the beginning
of the conversion. The conversion is monotonic with no missing codes.
The result of each successive comparison is stored in the successive approxima-
tion register (SAR) and, when the conversion is complete, the contents of the SAR
are transferred to the read-only ADC Data Register ($0F), and the conversion
complete flag, COCO, is set in the ADC Status and Control Register ($0E).
Any write to the ADC Status and Control Register will abort the current
conversion, reset the conversion complete flag (COCO) and a new conversion
starts on the selected channel.
At power-on or external reset, both the ADRC and ADON bits are cleared, thus
the ADC is disabled.
1. V
2. V
3. V
RL
specifications; and
RH
RL
RH
, but greater than V
–V
should be equal to or less than V
should be equal to or greater than V
RH
RL
, V
Freescale Semiconductor, Inc.
should be equal to or greater than 4 Volts.
RL
For More Information On This Product,
, (V
ANALOG TO DIGITAL CONVERTER
RH
Go to: www.freescale.com
+V
SS
RH
RL
February 24, 1999
RH
, converts to $00. Maximum and minimum ratings
)/4, or (V
and V
RH
converts to $FF. An input voltage equal to or less
and V
NOTE
RL
RL
RH
) are applied to a precision internal digital
for the ratiometric conversions. To main-
RL
+V
CC
as reference voltages. An input volt-
RL
;
)/2. Selection is done via the CHx
SS
but less than maximum
RH
as the supply
REV