Target Support Package™ TC2

C280x/C2833x ADC - Analog-to-Digital Converter (ADC)

Library

c280xdspchiplib and c2833xdspchiplib in Target Support Package™ TC2 software

Description

The C280x/C2833x ADC block configures the C280x/C2833x 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.

Output

The output of the C280x/C2833x ADC is a vector of uint16 values. The output values are in the range 0 to 4095 because the C280x/C2833x ADC is 12-bit converter.

Modes

The C280x/C2833x 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.

Dialog Box

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.
ePWMxA / ePWMxB / ePWMxA_ePWMxB — 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 Setting	Start of Conversion Choices
`A`	`Software`, `ePWMxA`, `XINT2_ADCSOC`
`B`	`ePWMxB`, `Software`
`A and B`	`Software`, `ePWMxA`, `ePWMxB`, `ePWMxA_ePWMxB`, `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. See Scheduling and Timing for more information on timing. To execute this block asynchronously, set Sample Time to -1, check the Post interrupt at the end of conversion box, and refer to Asynchronous Interrupt Processing for a discussion of block placement and other necessary settings.

To set different sample times for different groups of ADC channels, you must add separate C280x/C2833x 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 each conversion. The interrupt is always posted at the end of conversion. To execute this block asynchronously, set Sample Time to -1, and refer to Asynchronous Interrupt Processing for a discussion of block placement and other necessary settings.

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.