SLAU292C Datasheet, PDF (93/102 Pages) Texas Instruments – eZ430-Chronos™ Development Tool

Appendix A
SLAU292C – November 2009 – Revised December 2010
Frequently Asked Questions
A.1 FAQs
1. My eZ430-Chronos watch doesn't respond when I push buttons, instead it shows "Loct" in the
LCD?
"Loct" on the 7-segment LCD stands for "Lock" and indicates that the keylock is active. By holding "#"
and "DOWN" for 3 seconds simultaneously unlocks or locks the buttons. The LCDs shows "oPEn"
when the keylock is disabled.
2. Why doesn't my eZ430-Chronos watch always respond when buttons are pushed?
If buttons are pushed slowly (i.e., held down too long), button pushes are ignored.
3. Why doesn't my eZ430-Chronos respond when I try to push buttons in short intervals in PPT or
ACC mode?
Especially in PPT mode it is important to avoid bouncing of the buttons. Therefore, an artificial delay on
the receiver side is implemented. Button pushes are translated into keystrokes or mouse clicks only if
there is at least 0.5 seconds between two of them.
4. Is my eZ430-Chronos waterproof?
Yes, it is 30-m waterproof. This indicates that it resists splashes and rain. However, it cannot be used
while taking a shower, swimming, diving, surfing, snorkeling or any other water sports. Set the watch
before exposing it to excessive water. Pressing the buttons in water or heavy rainstorms may cause
water to enter the watch.
5. The reported temperature is incorrect, how can I calibrate the sensor?
A temperature offset is stored in Flash, which is calibrated at production. If the offset is erased or is
incorrect, it can be changed to an appropriate level; see Section 3.2.1.3 for details.
6. The reported altitude is incorrect, why is that and how can I calibrate the sensor?
The altitude is determined from barometric pressure. Therefore, the altimeter needs to be re-calibrated
as the pressure changes with the weather. See Section 3.2.1.4 for details on how to calibrate the
altimeter. In addition, the altitude is a function of the temperature in addition to the barometric
pressure. Therefore, the watch needs to have ambient temperature, wearing it on the arm or close to
the body may cause inaccurate measurements.
7. Why is there a timeout for the altimeter?
The altimeter algorithm is implemented according to an application report from VTI. It is not optimized
for ultra-low current consumption. For enhanced battery life, the altimeter stops operation after one
hour. It can be re-activated by pushing the "UP" button.
8. How can TI sell the eZ430-Chronos for only US$49?
The eZ430-Chronos kit is intended to be an attractive development kit and is not intended to be a
consumer product. Texas Instruments and the partner companies are sponsoring components or
services to increase the accessibility of flexible and innovative development systems to a broader
audience. Consumer products usually retail for higher prices.
9. Why are the backchannel pins not connected on the eZ430-Chronos PCB despite the fact that
the eZ430-Chronos debug interface supports the backchannel?
All pins of the CC430 were used for the LCD, buttons, or sensors.
10. Why is there no JTAG connector on the RF access point?
The access point is designed to be production ready and as small as possible. Therefore, no debug
connector is added. However, it may be reprogrammed by attaching a TI low power wireless debug
interface to the corresponding pads on the bottom side of the PCB, or using TI's CC1111EMK868-915.
SLAU292C – November 2009 – Revised December 2010
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