AS1545_1 AMSCO [austriamicrosystems AG], AS1545_1 Datasheet - Page 30

• Manufacturer Part Number: AS1545_1
• Description: Dual, 12-Bit, 1MSPS, SAR ADC
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1545
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
On top of the difference calculator, the ADC also provide us with information regarding input signals in quadrature (90
degrees phase difference) like the ones we would get from a position calculation system of a motor control.
In order for this mode to work, we must have SGL/DIFF=0, A2=1. A1=1. A0=0, according to what is specified in the
channel addresses table. Also, it is important to note that in order to read the data from the quadrature inputs
calculator we must read all 32 bits of data of the ADC, therefore reducing the overall sampling rate of the ADC by half.
The ADC provides us with the following information:
Figure 54. A to B phase
Direction of the rotor based on the DIR bit
If the rotor is rotating as the above picture, the direction bit is low.
If the rotor is rotating in the opposite direction to the above picture, the direction bit is high.
Note: This mode works only for SGL/DIFF=0, A2=1. A1=1. A0=0.
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- Phase A and Phase B bits, dividing the period into four quadrants
- DIR bit, which indicates the direction of the rotation of the rotor
- Counter, this is a 10 bit word that, in the case of using a step down in the rotor indicates the number of times the
step down has spun. The counter increases twice per period if DIR is equal zero and decreases twice per period if
DIR equals one.
Phase A
Phase B
Code 4095
Code 2048
Code 0
Cos
Sinus
Revision 1.01
Direction = 0
Direction = 1
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