Saturday, March 26, 2011

Magnetic Rotary Encoder to Microcontroller AS5145 circuit


Magnetic Rotary Encoder to Microcontroller AS5145 circuit
12-Bit Programmable Magnetic Rotary Encoder
The AS5145 is a contact less magnetic rotary encoder foraccurate angular measurement over a full turn of 360 degrees. It is a system-on-chip, combining integrated Hall elements,analog front end and digital signal processing in a single device. To measure the angle, only a simple two-pole magnet, rotating over the center of the chip, is required. The magnet may beplaced above or below the IC.The absolute angle measurement provides instant indication of the magnet’s angular position witha resolution of 0.0879ยบ = 4096 positions per revolution. This digital data is available as a serial bit stream and as a PWMsignal.An internal voltage regulator allows the AS5145 to operate at either 3.3V or 5V supplies.Typical magnet (6x3mm) and magnetic field distribution

Daisy Chain Mode
The Daisy Chain mode allows connection of severalAS5145’s in series, while still keeping just one digital input for data transfer (see “Data IN” in Figure 9). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (PDIO; pin 8) of the subsequent device. The serial data of all connected devices is read from the DO pin of the first device in the chain. The length of the serial bit stream increases with every connected device, it is n * (18+1) bits: n= number of devices. e.g. 38 bit for two devices, 57 bit for three devices, etcetc.
Download : AS5145 Datasheet