The Dac0 D/A Converter Output Registers; Figure 3-10. Adc High Byte Input Register - Brainboxes AD-593 User Manual

AD1200 Reference

Figure 3-10. ADC High Byte Input Register.

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ADCHI Input Register.
BIT 7
021B Read
Hex as
0

The DAC0 D/A Converter Output Registers.

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The DAC0 D/A Converter takes a 12 bit value that is the
digital representation of the required analogue output voltage.
This 12 bit value is written to two adjacent 8 bit, write only,
registers. The lower 8 bits of the 12 bit value are written to the
DAC0LO register. The upper 4 bits of the 12 bit value are
written to lower most 4 bits of the DAC0HI register. The upper
most 4 bits written to the DAC0HI register are "don't care" bits
but should always be set to 0 for compatibility with 16 bit D/A
software and data formats.
The DAC0HI and DAC0LO registers are WRITE ONLY, data
cannot be read back from them, instead a read of these registers
returns the latest output from the A/D converter, which occupies
the same i/o address space. Since reading ADCHI clears the A/D
Done bit in the ADCSR, attempts to "read back" the DAC0
output may cause strange errors to occur, resulting in A/D data
being lost.
The DAC data is in the form of right justified offset binary, ie a
value of 000hex gives the lowest output voltage whilst a value
of FFFhex gives the highest output voltage.
The value to write to the 12 bit D/A converter to obtain any
particular output voltage, DACVOLT, is obtained by:-
DAC0HI = DAC0DATA / 256
DAC0LO = DAC0DATA MOD 256
Page 62
BIT 6 BIT 5
Read Read
as as
0 0
BIT 4 BIT 3
Read ADC
as 11
0 Read
Register Map
BIT 2 BIT 1
ADC ADC
10 9
Read Read
__________ Write Only
remainder function
Chapter 3
BIT 0
ADC
8
Read