HT48R02N Holtek Semiconductor, HT48R02N Datasheet - Page 47

• Manufacturer Part Number: HT48R02N
• Description: (HT4xR0xx) Small Package 8-Bit OTP MCU
• Manufacturer: Holtek Semiconductor

www.DataSheet4U.com
Programming Considerations
When programming, special attention must be given to
the PCR[3:0] bits in the register. If these bits are all
cleared to zero no external pins will be selected for use
as A/D input pins allowing the pins to be used as normal
I/O pins. When this happens the internal A/D circuitry
will be power down. Setting the ADONB bit high has the
ability to power down the internal A/D circuitry, which
may be an important consideration in power sensitive
applications.
A/D Transfer Function
As the device contain a 12-bit A/D converter, its
full-scale converted digitised value is equal to FFFH.
Since the full-scale analog input value is equal to the
VDD voltage, this gives a single bit analog input value of
V
Rev.1.00
DD
/4096. The diagram show the ideal transfer function
Ideal A/D Transfer Function
A/D Conversion Timing
47
between the analog input value and the digitised output
value for the A/D converter.
Note that to reduce the quantisation error, a 0.5 LSB off-
set is added to the A/D Converter input. Except for the
digitised zero value, the subsequent digitised values will
change at a point 0.5 LSB below where they would
change without the offset, and the last full scale digitised
value will change at a point 1.5 LSB below the V
A/D Programming Example
The following two programming examples illustrate how
to setup and implement an A/D conversion. In the first
example, the method of polling the EOCB bit in the
ADCR register is used to detect when the conversion
cycle is complete, whereas in the second example, the
A/D interrupt is used to determine when the conversion
is complete.
HT46R01B/02B/01N/02N
HT48R01B/02B/01N/02N
December 15, 2009
DD
level.