User`s guide

5-2 Intel
®
StrongARM
®
SA-1110 Microprocessor Development Board User’s Guide
Analog I/O
The single cell Li-Ion battery has critical voltage thresholds as follows:
Table 5-2. Battery Voltage Level Indications
The UCB1300 is not sufficiently accurate to monitor Li-ion battery voltages. A one time per
system calibration step must be performed and the conversion factor saved in the system flash
memory for use by the OS and applications. The system software must provide 0.05 V of hysteresis
and rolling averages to eliminate noise and power fluctuations.
5.1.2 Battery Temperature
The SA-1110 Development Board battery temperature is monitored with an Analog Devices
TMP37 low-power, low-cost, thermometer device. This device is accurate to 2% and converts
temperature from
°
C to an analog voltage with a 20mV/C
°
conversion factor. The device output is
offset from absolute zero and will output the following voltages:
Table 5-3. Battery Temperature Indications
5.1.3 Analog Spare
Spare analog input for user definable inputs.
2 cell
Li-Ion
Voltage
UCB1300
ADC decimal
value
(estimated)
Indication
2.7V 270
Bottom Of Charge (BOC)—Must not fall below this voltage or battery
service life may diminish.
3.0V 300
Sleep Threshold Voltage (STV)—10% charge remaining. Force into sleep
mode or data may be lost.
4.1V 410
Top Of Charge (TOC)—Must not exceed this voltage (stop charging
immediately).
>4.2V >420
Danger—Sound alarms, flash LEDs (personal safety and fire hazard, stop
charging immediately).
Temp
C
°
TMP37
Output
UCB1300
ADC decimal
value (estimated)
Indication
25
°
0.50 V 62 Room temperature.
40
°
0.80 V 100 Battery High Temp—stop charging immediately.
>50
°
>1.00 V >125
Danger
Sound alarms, flash LEDs.
Personal safety and fire hazard.
Stop charging.