p p m m o o d d g g y y r r o o 2 2 ? ? r r e e f f e e r r e e n n c c e e m m a a n n u u a a l l revision: october 24, 2012 note: this document applies to rev a of the board. 1300 ne henley court, suite 3 pullman, wa 99163 (509) 334 6306 voice | (509) 334 6300 fax doc: 502-232 page 1 of 2 overview the pmodgyro2 features the analog devices adxrs453 high performance, digital output gyroscope that is ideal for systems in need of a gyroscope for high vibration environments. functional description the pmodgyro2 is a single-axis high performance gyroscope that utilizes a standard 6-pin connector and communicates via a serial peripheral interface (spi) bus. interface the pmodgyro2 interfaces with systems using standard spi transmission protocol. (see table 1 for signal descriptions.) the module is set up for clock phase = clock polarity = 0 or spi mode 0. users should drive spi communication only to a maximum frequency of 8mhz. this analog devices gyroscope utilizes a 32- bit command/response system to facilitate communication with user devices. system commands are sent to the pmod during one 32-bit transmission sequence, and it returns a response during the next 32-bit transmission sequence. this message layout ensures that the very first module response is always 0x00000001. (see table 2 for details on bit definitions.) when users assert chip select for each command, the pmodgyro2 begins latching rate data in case the command is a data request. the device then sends the data via the response in the next command sequence. the pmodgyro2 is capable of sending three different types of command packets and returning four different response packets. (see tables 3 and 4 for a breakdown of the allowed spi commands and responses.) even though commands are 32-bits wide and the data part is 16-bits wide, each register in features include: ? simple spi interface ? 300/sec angular rate sensing ? ultrahigh vibration rejection .01/sec/g ? excellent 16/hour null bias stability ? internal temperature compensation ? continuous self-test the device is only 8-bits wide. due to the differences in widths, a read command will return the register requested and the next sequential register in the memory map. the same width ratio applies to a write command. users should address read and write commands to even registers only . users that desire access to an odd register must address commands to the previous (even) register. for simple acquisition of data, users should issue an spi command in the sensor data format. this will return an spi response in the sensor data format on the next spi transmission. the adxrs453 has a continuous self-test function that tests the complete electromechanical system and reports errors to the user. the adxrs453 returns results to users via the fault register. the status of the pmodgyro2 is included in most responses the pmodgyro2 also prevents
pmodgyro2 reference manual www.digilentinc.com page 2 of 2 copyright digilent, inc. all rights reserved. other product and company names mentioned may be tradema rks of their respective owners. temporary spikes in data from causing a failing status response by filtering raw data from the self-test before sending a pass/fail status. the module stores both the raw data and the filtered data in the hicstx and locstx registers. users may access this data should they be concerned about these energy spikes. the temperature sensor data is useful for temperature compensation of the rate data and is also directly available to the user. to get the temperature sensor data users must simply execute a read command of the temx registers from the device. table 1: interface connector signal description note: for more information on the gyro2 module interface, see the adxrs453 datasheet available online from analog devices at www.analog.com . table 2: spi bit definitions bits description sq[2:0] sequence bits sm[2:0] sensor module bits (always 0b000) a[8:0] register address d[15:0] data p command odd parity spi spi command/response error re request error du data unavailable st[1:0] status bits p0 response, odd parity, bits[31:16] p1 response, odd parity, bits[31:0] table 3: spi commands table 4: spi responses connector j1 pin signal description 1 cs chip select 2 mosi master out/slave in 3 miso master in/slave out 4 sclk serial clock 5 gnd power supply ground 6 vcc power supply (3.3v)
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