Hello Community,
I want to develop motor control application software for a MCSPTR2A5775E motor kit with MPC5775E board using the MBDT. Unfortunately, the MBDT is missing critical functions for a standard motor control application. Specifically, I am facing the following problem:
Two essential functions, the evaluation of resolver/speed feedback and generation of the three phase PWM output signals, are realized using the eTPU peripheral. The MBDT does not feature blocks/functions set up the eTPU related functions. This was confirmed by NXP, see answer in an earlier topic:
Hence, I am trying to find a way to create the above functions without eTPU. I want to share with you my approach and to kindly ask the support to answer my questions.
Alternative Solution for Resolver Feedback:
The resolver COS and SIN feedback is normally evaluated through SDADC, as stated in the application note:
- Sine --> SDADC 1: M_ANA0_SDA0 ANA0 /SDA0
- Cosine --> SDADC 4 M_ANB0_SDD0 ANB0 /SDD0
Since SDACD is not available, EQADC might be used instead. I would configure the EQADC as follows (example for COS evaluation on channel ANB0):
Question for support:
- In general: is this possible?
- Can you confirm the followin: With this approach I "loose" two EQADC channels, which are normally needed to read the current and voltage measurements. I understood, that this board does only have a max. of 4 EQADC channels.
Alternative Solution for Resolver Excitation:
Resolver excitation is done using ETPUA6 /GPIO120. To bypass the eTPU I intend to write a 10kHz square wave signal directly to the GPIO120 pin (PTD24):
Question for support:
- Is this approach feasible?
- If not, what else can I use?
Alternative Solution for Three Phase PWM:
According to the application note the kit uses the following eTPU channels and pins (GPIOM 130...135) for the PWM generation/output:
- ETPUA16 /GPIO130 PWMM Phase A High
- ETPUA17 /GPIO131 PWMM Phase A Low
- ETPUA18 /GPIO132 PWMM Phase B High
- ETPUA19 /GPIO133 PWMM Phase B Low
- ETPUA20 /GPIO134 PWMM Phase C High
- ETPUA21 /GPIO135 PWMM Phase C Low
Since eTPU cannot be used, I scanned the documentation and communities for alternative solutions:
- FlexPWM: The motor control demo examples for MPC5774 use flexpwm blocks, which (from my understanding) are not available for MPC5775E. --> not an option
- eMIOS: this thread https://community.nxp.com/t5/Model-Based-Design-Toolbox-MBDT/MPC5777-MBD-ADC-Module/m-p/1212272 proposes to use eMIOS channels for PWM creation. I had a look and I found that neither eMIOS channel is connected to the correct pins (GPIOM 130...135).
My questions @mariuslucianand:
- How can I access the right GPIOM pins with eMIOS?
- Can the pin-Assignment be rearranged?
- If this is not possible, what else can I do? Write to GPIOM pins directly?
Thank you so much for reading such a long text and many thanks in advance for help.
Nils
