C280x/C2833x ADC

Analog-to-Digital Converter (ADC)

Library

Embedded Coder® Support Package for Texas Instruments™ C2000™ Processors/ C280x

Embedded Coder Support Package for Texas Instruments C2000 Processors/ C2833x

Description

The ADC block configures the ADC to perform analog-to-digital conversion of signals connected to the selected ADC input pins. The ADC block outputs digital values representing the analog input signal and stores the converted values in the result register of your digital signal processor. You use this block to capture and digitize analog signals from external sources such as signal generators, frequency generators, or audio devices. With the C2833x, you can configure the ADC to use the processor DMA module to move data directly to memory without using the CPU. This frees the CPU to perform other tasks and increases overall system capacity.

Output

The output of the ADC is a vector of uint16 values. The output values are in the range 0 to 4095 because the ADC is 12-bit converter.

Modes

The ADC block supports ADC operation in dual and cascaded modes. In dual mode, either module A or module B can be used for the ADC block, and two ADC blocks are allowed in the model. In cascaded mode, both module A and module B are used for a single ADC block.

Parameters

ADC Control Pane

Module

Specifies which DSP module to use:

  • A — Displays the ADC channels in module A (ADCINA0 through ADCINA7).

  • B — Displays the ADC channels in module B (ADCINB0 through ADCINB7).

  • A and B — Displays the ADC channels in both modules A and B (ADCINA0 through ADCINA7 and ADCINB0 through ADCINB7).

Conversion mode

Type of sampling to use for the signals:

  • Sequential — Samples the selected channels sequentially.

  • Simultaneous — Samples the corresponding channels of modules A and B at the same time.

Start of conversion

Type of signal that triggers conversions to begin:

  • Software — Signal from software. Conversion values are updated at each sample time.

  • ePWM#A / ePWM#B / ePWM#A_ePWM#B — Start of conversion is controlled by user-defined PWM events.

  • XINT2_ADCSOC — Start of conversion is controlled by the XINT2_ADCSOC external signal pin.

The choices available in Start of conversion depend on the Module setting. The following table summarizes the available choices. For each set of Start of conversion choices, the default is given first.

Module SettingStart of Conversion Choices
ASoftware, ePWM#A, XINT2_ADCSOC
BePWM#B, Software
A and BSoftware, ePWM#A, ePWM#B, ePWM#A_ePWM#B, XINT2_ADCSOC
Sample time

Time in seconds between consecutive sets of samples that are converted for the selected ADC channel(s). This is the rate at which values are read from the result registers. To execute this block asynchronously, set Sample Time to -1, check the Post interrupt at the end of conversion box.

To set different sample times for different groups of ADC channels, you must add separate ADC blocks to your model and set the desired sample times for each block.

Data type

Date type of the output data. Valid data types are auto, double, single, int8, uint8, int16, uint16, int32, or uint32.

Post interrupt at the end of conversion

Select this check box to post an asynchronous interrupt at the end of the set of conversions. The interrupt is posted at the end of conversion. To execute this block asynchronously, set Sample Time to -1.

Input Channels Pane

Number of conversions

Number of ADC channels to use for analog-to-digital conversions.

Conversion no

Specific ADC channel to associate with each conversion number.

In oversampling mode, a signal at a given ADC channel can be sampled multiple times during a single conversion sequence. To oversample, specify the same channel for more than one conversion. Converted samples are output as a single vector.

Use multiple output ports

If more than one ADC channel is used for conversion, you can use separate ports for each output and show the output ports on the block. If you use more than one channel and do not use multiple output ports, the data is output in a single vector.