HT46R064G/065G/0662G
Enhanced A/D Type 8-Bit OTP MCU with OPA
Programming Considerations
When programming the devices, special attention must be given to the PCRn bits in the PCR register
for the HT46R064G and HT46R065G devices. 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 or other
pin-shared functional pins. When this happens, the internal A/D circuitry will be power down. For the
HT46R0662G device, 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 VDD/4096. The diagram show the ideal transfer function 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 offset 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 VDD level.
1
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5
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Ideal A/D Transfer Function
Rev. 1.00
75
March 3, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
