INSTASPIN-BLDC: IQ math for Instaspin

Javier Vara

Hello,

I've got some questions regarding the IQ math system used in Instaspin.

1) The controller runs by default in IQ24. Is it possible to change that to, let's say, IQ25 or IQ26? if it is possible, how is it done?

2) If all the controller runs in per unit, the maximum values you would expect would be between +-1, therefore, why not use IQ30 to increase accuracy?

3) I read some posts about moving the controller from fixed point math to float, is this possible? I've got the floating point unit enabled but I believe it is only used for external operations in the main loop.

Thanks!

over 8 years ago

0 ChrisClearman over 8 years ago

TI__Guru** 119680 points

1. not possible
2. there are calculations done in per unit that need to go beyond +/-1
3. you can't update the ROM to FPU. You are using FPU for your calculations outside the ROM only. Future versions of InstaSPIN (on new devices) will be in full floating point as all devices in the future will include FPU

0 Javier Vara over 8 years ago in reply to ChrisClearman

Expert 1645 points

Thanks for the answers.

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INSTASPIN-BLDC: IQ math for Instaspin