LaunchPad controlling up to 8 RC Servos

[tech_juggernaut 5]

Thanks!

 

So in the final code, TIMER0_A0_VECTOR is called when the count matches CCR0, and then ADC10_VECTOR is called when the count resets to 0?

 

I guess I was thinking it generated an Interrupt based on the change in the levels of the analog signals?...

[oPossum 1,083]

ADC10_VECTOR is called when the ADC is done with conversion, or if DTC (data transfer controller) is being used then it is called at the end of the DTC cycle.

 

The start of ADC conversion has to be triggered by code - it doesn't sense a change in voltage.

[RobG 1,892]

When CCR reaches your count value, TIMER0_A0_VECTOR is called. Servos are then updated and ADC sampling/conversion is started (all inside timer's ISR.) After ADC is done, ADC10_VECTOR is called and new servo positions are calculated.

[zeke 693]

Just to clarify, does the const declaration remove the array from RAM and stuff it into FLASH?

[oPossum 1,083]

Yes, using const will usually put stuff in flash rather than RAM. This is not part of the C/C++ spec, but rather an obvious and common optimization done by compilers for embedded systems. Some compilers may require a special #pragma or other directive to ensure placement in flash - CCS and MSPGCC do not. Linker files can also be used to effect proper placement, but that is usually only done in special cases.

[tech_juggernaut 5]

Do you know how I could translate the CCR values to an actual position in degrees? I thought it would be cool to be able to output its actual position to a PC via serial. Is something like that possible? Thanks!

[oPossum 1,083]

int deg = ((CCR - 187) * 184) >> 8;

[spoil9 1]

Rob,

 

Thank you for posting all this sample code. Not being a C programmer, I'm still a little confused by it but I'm learning.

 

I have a question though, when watching all the videos I noticed that the servos only rotated 90 degrees, which mine did as well. Is this just the way the way the 430 handles servos or is there something I can change in the code to allow a full 180 degree rotation?

 

Thanks.

[RobG 1,892]

You can change it in the code by adjusting min and max CCR value.