LM3S328 Luminary Micro, Inc., LM3S328 Datasheet - Page 199

• Manufacturer Part Number: LM3S328
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

11.2.6
11.3
11.3.1
11.3.2
October 8, 2006
analog stimulus. This mode is available through the ADC Test Mode Loopback (ADCTMLB)
register (see page 224).
Internal Temperature Sensor
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 11-2 on page 199.
Figure 11-2. Internal Temperature Sensor Characteristic
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 on page 76). 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.
2.
Sample Sequencer Configuration
Configuration of the Sample Sequencers is slightly more complex than the module initialization
since each sample sequence is completely programmable.
The configuration for each Sample Sequencer should be as follows:
1.
2.
Enable the ADC clock by writing a value of 0x00010000 to the RCGC1 register in the System
Control module.
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.
Ensure that the Sample Sequencer is disabled by writing a 0 to the corresponding ASEN bit in
the ADCACTSS register. Programming of the Sample Sequencers is allowed without having
them enabled. Disabling the Sequencer during programming prevents erroneous execution if
a trigger event were to occur during the configuration process.
Configure the trigger event for the Sample Sequencer in the ADCEMUX register.
Preliminary
LM3S328 Data Sheet
199