Steven Kay / SD20

This is a driver to control the SD20 20 Channel I2C to Servo Driver Chip from www.robot-electronics.co.uk (http://www.robot-electronics.co.uk/htm/sd20tech.htm). This driver will allow a servo channel to be started up, stopped and the duty cycle altered in standard mode. No attempt to include the extended mode is included.

Diff: SD20.cpp

Revision:
1:6557cf755742
Parent:
0:870a29ad1074
Child:
2:b6789ad2af2b
Child:
4:5ccaaacec14f
--- a/SD20.cpp	Sun Jan 24 14:39:33 2016 +0000
+++ b/SD20.cpp	Sun Jan 24 15:10:48 2016 +0000
@@ -1,57 +1,74 @@
 #include "mbed.h"
 #include "SD20.h"
       
-SD20::SD20(I2C *bus,int I2CAddress, int BusHz)
+SD20::SD20(I2C *bus)
 {
     _bus = bus;
-    deviceAddress = I2CAddress;
-    BusHz = BusHz;
-    _bus -> frequency(BusHz);
+    _bus -> frequency(BUS_FREQ);
 }
 
-int SD20::UpdatePWM(char *DataOutput)
+int SD20::UpdateChannel(char *newDutyCycle)
 {
-        if(_bus -> write(deviceAddress,(char*)DataOutput,OUT_BUF_LEN))
+        // Output new duty cycle to SD20, return 0 if successful, 1 if unsuccessful
+        if(_bus -> write(SD20_ADDRESS,newDutyCycle,OUT_BUF_LEN))
         {
             printf("I2C Failed to write\r\n");
             return 1;
         }
         else
         {
-            printf("0x%02x sent to Reg: 0x%02x\r\n",*(DataOutput+1),*DataOutput);
+            printf("0x%02x sent to Reg: 0x%02x\r\n",*(newDutyCycle+1),*newDutyCycle);
             return 0;
         }
 }
 
-int SD20::StartStopPWM(int Channel,bool Start)
+int SD20::StartStopChannel(uint8_t ServoChannel,bool Start)
 {
+        // Startup a new channel, return 0 if successful, 1 if unsuccessful
         if(Start == CHANNEL_START)
         {
-            int DataOutput[] = {Channel,0x01};
-            if(_bus -> write(deviceAddress,(char*)DataOutput,OUT_BUF_LEN))
+            char newDutyCycle[] = {ServoChannel,CHANNEL_START};
+            if(_bus -> write(SD20_ADDRESS,newDutyCycle,OUT_BUF_LEN))
             {
                 printf("I2C Failed to write\r\n");
                 return 1;
             }
             else
             {
-                printf("0x%02x sent to Reg: 0x%02x\r\n",*(DataOutput+1),*DataOutput);
+                printf("0x%02x sent to Reg: 0x%02x\r\n",*(newDutyCycle+1),*newDutyCycle);
                 return 0;
             }
         }
+        
+        // Stop channel, return 0 if successful, 1 if unsuccessful
         else
         {
-           int DataOutput[] = {Channel,0x00};
-            if(_bus -> write(deviceAddress,(char*)DataOutput,OUT_BUF_LEN))
+           char newDutyCycle[] = {ServoChannel,CHANNEL_STOP};
+            if(_bus -> write(SD20_ADDRESS,newDutyCycle,OUT_BUF_LEN))
             {
                 printf("I2C Failed to write\r\n");
                 return 1;
             }
             else
             {
-                printf("0x%02x sent to Reg: 0x%02x\r\n",*(DataOutput+1),*DataOutput);
+                printf("0x%02x sent to Reg: 0x%02x\r\n",*(newDutyCycle+1),*newDutyCycle);
                 return 0;
             }
         }
 }
 
+int SD20::SetStandardMode()
+{
+        char outputBuf[] = {STD_ETD_MODE_CTRL,STD_MODE};
+        if(_bus -> write(SD20_ADDRESS,outputBuf,OUT_BUF_LEN))
+        {
+            printf("I2C Failed to write\r\n");
+            return 1;
+        }
+        else
+        {
+            printf("0x%02x sent to Reg: 0x%02x\r\n",*(outputBuf+1),*outputBuf);
+            return 0;
+        }    
+}
+