#243 simple MCP3202 SPI test

wiringPi/test/wiringpi_spi_test1_mcp3202.c

@@ -0,0 +1,112 @@
+// WiringPi test program: SPI functions (need MCP3202 hardware @ CE1, ch0=Vdd, ch1=Vdd/2)
+// Compile: gcc -Wall wiringpi_spi_test1_mcp3202.c -o wiringpi_spi_test1_mcp3202 -lwiringPi
+
+#include <unistd.h>
+#include <stdint.h>
+#include <signal.h>
+#include <time.h>
+#include "wpi_test.h"
+#include <wiringPiSPI.h>
+
+const float fRefVoltage = 3.3f;
+const float fResolution = 4096; //12-Bit
+const int spiChannel = 1;
+const int spiSpeedInit = 250000; // Hz
+
+
+int AnalogRead(int spiChannel, int analogChannel, int* returnvalue) {
+    if (analogChannel<0 || analogChannel>1) {
+        return -1;
+    }
+
+    unsigned char spiData[3];
+    unsigned char chanBits;
+
+    if (analogChannel == 0) {
+        chanBits = 0b11010000;
+    } else {
+        chanBits = 0b11110000;
+    }
+    spiData[0] = chanBits;
+    spiData[1] = 0;
+    spiData[2] = 0;
+    *returnvalue = wiringPiSPIxDataRW(0, spiChannel, spiData, 3);
+    return ((spiData [0] << 9) | (spiData [1] << 1) | (spiData[2] >> 7)) & 0xFFF;
+}
+
+
+int main(int argc, char *argv []){
+
+    int hSPI;
+    int CH0,CH1;
+    float value0, value1;
+    int returnvalue;
+    int spiSpeed;
+    int major, minor;
+
+    wiringPiVersion(&major, &minor);
+    printf("Testing SPI functions with WiringPi %d.%d\n",major, minor);
+    printf("------------------------------------------\n\n");
+
+    wiringPiSetup();
+    spiSpeed = spiSpeedInit;
+    for (int testno=0; testno<=2; testno++) { 
+        printf("\nTest 5d with %g MHz SPI Speed\n", spiSpeed/1000000.0f);
+        if ((hSPI = wiringPiSPISetup (spiChannel, spiSpeed)) < 0) {
+            FailAndExitWithErrno("wiringPiSPISetup", hSPI);
+        }
+
+        int hSPIOld=hSPI;
+        //printf("\nSPI fd = %d\n call close now\n", hSPI);
+        int ret = wiringPiSPIClose(spiChannel);
+        if (ret!=0) {
+            FailAndExitWithErrno("wiringPiSPIClose", ret);
+        }
+
+        if ((hSPI = wiringPiSPIxSetupMode(0, spiChannel, spiSpeed, 0)) < 0) {
+            FailAndExitWithErrno("wiringPiSPIxSetup", hSPI);
+        }
+
+        CheckSame("SPISetup, Close and SPIxSetup handle", hSPI, hSPIOld);
+        
+        delayMicroseconds(500000);
+        returnvalue = -1;
+        CH0 = AnalogRead(spiChannel, 0, &returnvalue);
+        CheckSame("CH0 wiringPiSPIxDataRW return", returnvalue, 3);
+        value0 = CH0 * fRefVoltage / fResolution;
+        CheckSameFloat("CH0 value (VDD)", value0, 3.3f);
+        printf("\n");
+        
+        delayMicroseconds(500000);
+        returnvalue = -1;
+        CH1 = AnalogRead(spiChannel, 1, &returnvalue);
+        CheckSame("CH1 wiringPiSPIxDataRW return", returnvalue, 3);
+        value1 = CH1 * fRefVoltage / fResolution;
+        CheckSameFloat("CH1 value (1/2)", value1, 1.65f);
+        printf("\n");
+
+        ret = wiringPiSPIxClose(0, spiChannel);
+        CheckSame("wiringPiSPIxClose result", ret, 0);
+        if (ret!=0) {
+            FailAndExitWithErrno("wiringPiSPIxClose", ret);
+        }
+        ret = wiringPiSPIxGetFd(0, spiChannel);
+        CheckSame("Fd after wiringPiSPIxGetFd", ret, -1);
+
+        ret = wiringPiSPIGetFd(spiChannel);
+        CheckSame("Fd after wiringPiSPIGetFd", ret, -1);
+
+        spiSpeed += spiSpeed;
+    }
+
+    printf("\n");
+    hSPI = wiringPiSPISetup (3, spiSpeedInit);
+    CheckSame("\nwiringPiSPISetup with wrong channel", hSPI, -22);
+
+    // will result in exit! - not useful in test code
+    //hSPI = wiringPiSPIxSetupMode (3, 0, spiSpeedInit,0);
+    //CheckSame("\nwiringPiSPISetup with wrong channel", hSPI, -22);
+
+    return UnitTestState();
+}
+