User Manual

Software Design
Wireless Sensing Triple Axis Reference design, Rev. 0.9
44 Freescale Semiconductor
Figure 5-8Calibration data ‘K’ (0x4B)
5.4.4 Calibration process ‘k’ (0x6B)
The calibration process is initiated by a ‘k’ command from the PC, followed by 6 bytes of calibration data.
These are to be stored in the Flash memory of the Sensor Board being used. More in chapter 5.3.2.5
ZSTAR_CALIB.
The calibration data is just 6 bytes in the following sequence:
Xval0, Xval1, Yval0, Yval1, Zval0, Zval1 - 0g and 1g calibration accelerometer binary values for X-, Y-
and Z-axis. No response from the demo is provided. Verification of the calibration data stored can be done
using the Calibration data ‘K’ (0x4B) command.
Figure 5-9Calibration process ‘k’ (0x6B)
5.4.4.1 Remaining STAR demo commands
The remaining STAR commands, such as 'F', 'G', 'H', '0', '1', '2', '3' and 'E' are not implemented in the
ZSTAR demo.
5.4.5 Additional ZSTAR commands
5.4.5.1 g-select reading ‘G’ (0x47)
The ZSTAR demo allows dynamic selection of the g-range for the accelerometer sensor (see details in
chapter 3.4.2 g-select connections), thus additional commands are implemented to read and change the
g-range.
When the PC issues a ‘G’ command, the ZSTAR demo responds with the g-range actually selected. A ‘0’,
‘1’, ‘2’ or ‘3’ character is returned where ‘0’ is for the 1.5g range, ‘1’ for 2.0g , ‘2’ for 4.0g and ‘3’ for the
6.0g range. If a different sensor (e.g. MMA7261Q) is implemented on the Sensor Board, the g-ranges are
2.5g, 3.3g, 6.7g and 10g respectively.
PC to demo
demo to PC
x(0g)
‘X’ ‘Y’ ‘Z’
‘K’
x(1g) y(0g) y(1g) z(0g) z(1g)
PC to demo
demo to PC
x(0g)
‘k’
x(1g) y(0g) y(1g) z(0g) z(1g)