LM3S6753 Datasheet, PDF (287/625 Pages) Texas Instruments – Stellaris LM3S6753 Microcontroller

Stellaris® LM3S6753 Microcontroller
12.2.7
Internal Temperature Sensor
The temperature sensor serves two primary purposes: 1) to notify the system that internal temperature
is too high or low for reliable operation, and 2) to provide temperature measurements for calibration
of the Hibernate module RTC trim value.
The temperature sensor does not have a separate enable, since it also contains the bandgap
reference and must always be enabled. The reference is supplied to other analog modules; not just
the ADC.
The internal temperature sensor provides an analog temperature reading as well as a reference
voltage. The voltage at the output terminal SENSO is given by the following equation:
SENSO = 2.7 - ((T + 55) / 75)
This relation is shown in Figure 12-5 on page 287.
Figure 12-5. Internal Temperature Sensor Characteristic
12.3
12.3.1
Initialization and Configuration
In order for the ADC module to be used, the PLL must be enabled and using a supported crystal
frequency (see the RCC register). Using unsupported frequencies can cause faulty operation in the
ADC module.
Module Initialization
Initialization of the ADC module is a simple process with very few steps. The main steps include
enabling the clock to the ADC and reconfiguring the sample sequencer priorities (if needed).
The initialization sequence for the ADC is as follows:
1. Enable the ADC clock by writing a value of 0x0001.0000 to the RCGC0 register (see page 108).
2. If required by the application, reconfigure the sample sequencer priorities in the ADCSSPRI
register. The default configuration has Sample Sequencer 0 with the highest priority, and Sample
Sequencer 3 as the lowest priority.
April 05, 2010
287
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