3.2 Performing an AD Scan

Description

An A/D scan is similar to an A/D sample except that it performs several conversions on a specified range of input channels with each function call. The Universal Driver function for performing an A/D scan is dscADScan.

Step-By-Step Instructions

Create and initialize an A/D settings structure (DSCADSETTINGS).

Call dscADSetSettings and pass it a pointer to this structure in order to setup the driver for A/D operations.

Create and initialize an A/D scan structure (DSCADSCAN).

Create and initialize a sample buffer of type DSCSAMPLE.

Call dscADScan() and pass it a pointer to your scan structure - this will generate an A/D conversion for each channel in your scan range and the results will be stored in the sample_values element of your DSCADSCAN structure.

NOTE: You must always remember to allocate enough memory for your sample buffer (in this case, the WORD sample_values). The driver assumes that your application has allocated at least the amount of memory given in the following formula:

Memory = sizeof(WORD) * ( high_channel - low_channel + 1 )

Example of Usage for A/D Scan

... 
DSCB dscb; 
DSCADSETTINGS dscadsettings; 
DSCADSCAN dscadscan; 

/* Step 1 */ 

dscadsettings.current_channel = 0; 
dscadsettings.gain = 0; 
dscadsettings.range = 0; 
dscadsettings.polarity = 0; 
dscadsettings.load_cal = 0; 

/* Step 2 */ 

if ((result = dscADSetSettings(dscb, &dscadsettings)) != DE_NONE) 
    return result; 

/* Step 3 */ 

dscadscan.low_channel = 0; 
dscadscan.high_channel = 3; 

/* Step 4 */ 

dscadscan.sample_values = (DSCSAMPLE*)malloc(sizeof(DSCSAMPLE) * (dscadscan.high_channel - dscadscan.low_channel + 1)); 
memset(dscadscan.sample_values, 0, sizeof(DSCSAMPLE) *(dscadscan.high_channel - dscadscan.low_channel + 1)); 

/* Step 5 */ 

if ((result = dscADScan(dscb, &dscadscan, dscadscan.sample_values)) != DE_NONE) 
    return result;