TI C2000 Piccolo单芯片——实现双轴伺服电机和马达控制

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TI C2000 Piccolo单芯片——实现双轴伺服电机和马达控制 [复制链接]

【转自https://e2echina.ti.com/question_answer/microcontrollers/c2000/f/56/p/165972/488430?keyMatch=f280049%20CLB&tisearch=Search-CN-Everything】
直播讲师：谭徽
直播Q&A：

1 . C2000 Piccolo单芯片主频能运行到多少？

A： 最高的是F28075芯片可以到120MHz，今天会介绍的最新F28004x是100MHz

2 . F280049C 可以连接几个编码器，采用哪种协议？

A： 最多两个绝对式编码器，基本支持所有类型编码器和协议

3 . 可以支持CW/ CCW脉冲吗？

A： 专业的问题，之前的所有芯片都不行，今天介绍的F28004x的QEP现在已经能够支持

4 . 开发环境使用哪个

A： 至少需要CCSv8

5 . 支持rtos吗

A： 支持TI-RTOS

6 . 这个芯片是不是可以实现机器人推一下他不倒？

A： 这个问题更多在软件算法和芯片的处理能力上，而后者显然是F28004x能够支持的。

7 . C2000是否可以做音圈控制？

A： 这个目前好像还没有，我们需要了解更多完整的需求来看看是否有可能

8 . 这里的AD转化器是一个还是并联多个？同时采样？还是排队转换

A： 有三个独立的ADC转换器，并行采样和转换

9 . 现在官方有没有f004x launchpad?

A： 有的，请在TI官网搜索P/N: LAUNCHXL-F280049C

10 . 请问28004X 是否有相对应的数字电源解决方案

A： 有的，包括PFC和逆变等，请下载c2000 digital power SDK安装在默认路径后在以下路径查找：C:\ti\c2000\C2000Ware_DigitalPower_SDK_1_01_00_00\solutions

11 . 为什么delfino系列没有内置观测器算法的芯片，而picoolo系列有？

A： 因为Delfino通常是偏高端的应用，对于电机控制来讲，通过也是会需要编码器的场合，因此我们没有集成位置观测器在Delfino芯片里

12 . 支持绝对值编码器接口？ 比如ssi biss

A： 是的，使用CLB模块可支持

13 . 该芯片支持3路ADC同步转换而不是序列转换？

A： 是的，请查看问题#112的回答

14 . 三路同时采样都可以达到3.5M采样路吗

A： 是的，独立采样

15 . 有旋变的例程？

A：是的，你可以下载controlsuite安装在默认路径后在以下路径查找：C:\ti\controlSUITE\libs\app_libs\motor_control\libs\resolver\v101

16 . 除法运算需要几个时钟周期？

A： 使用FPU浮点单元或者TMU三角函数硬件加速单元，都只需要1个时钟周期

17 . 在传感器接口方面，目前有旋转变压器的sensor接口吗

A： 如果是外部器件，TI可以提供PGA411芯片，如果是片上软解，TI C2000可以通过DAC产生励磁通过ADC采样正余弦信号然后使用CLA或者C28x内核进行解码，我们也提供了对应的解决方案和例程。

18 . 咱们样板的原理图 pcb有相关下载链接吗

A：请下载C2000WARE安装在默认路径后在以下路径查找：C:\ti\c2000\C2000Ware_1_00_06_00\boards\controlCARDs\TMDSCNCD280049C

19 . RAM和Flash有多大？

A： 请查看数据手册，100KB和256KB

20 . C2000 Piccolo微控制器提供哪些系统保护方面功能？

A： 模拟信号可以直接使用片上ADC后端处理单元PPB产生数字信号，或者直接使用片上CMPSS产生数字信号通过X-BAR送至EPWM模块直接保护，而如果采用Sigma-delta数字滤波器，我们片上的SDFM模块也可以比较并产生数字信号，同样经过X-BAR送到EPWM模块进行保护。

21 . f28004x带外部总线没有?

A： 没有

22 . 还想问一下，实现单芯片的双轴电机控制，以往的28069可以胜任吗，我们这边有尝试，用28069控制两台电机，但是效果不是太好，是不是计算资源不够，还是软件架构存在问题

A： 理论上也是可以的，可能在于其它功能比较多占用了控制性能的资料，有其它用户使用F28035也可以控制两台电机的

23 . 能实现编码器的分频输出吗？

A： 可以的，我们提供两种解决方案，一是使用片上硬件CLB模块，二是使用片上type 4 EPWM模块进行模拟

24 . 可以连接串行通信的编码器吗？

A： 可以的，你可以直接使用RS485进行通讯，也可以使用片上的CLB模块直接进行解码

25 . 用来做三闭环是完全够了吧？

A： 从处理器能力上来讲，也是完全没有问题的

26 . 功耗会不会很大

A： 不会的，大概只有100mA左右

27 . CAN C2000 series support EtherCAT slave？

A： Yes. You will find projects supporting the EtherCAT slave stack from the EtherCAT Technology Group and drivers have been optimized to run on the C28 core. e2e.ti.com/.../ethercat-and-c2000-mcus-real-time-communications-meets-real-time-control

28 . Can we use the assembly language to program the software? Is it the same as ;used?

A： Yes. You certainly can program in assembly language using the C2000 Code Composer Studio tools.

29 . is there a plan for CAN FD

A： Yes. CAN-FD will be supported in the future. But that’s all that can be said at this time.

30 . is there any supportance for variable carrier frequency

A： Yes, our PWMs are very capable of handling this. You will find examples of this in some of our digital power control reference designs. Typically, this technique is not used in our motor control examples.

31 . Can the F280049C really replace my FPGA for the current loop?

A： Yes! We think so. Dr. Tan will show you why we think so in just a few minutes. The current loop time will be less than 1.6 us and FCL can deliver 50% of your PWM carrier frequency as control bandwidth. For example, a 10 kHz carrier delivers 5kHz of control bandwidth!

32 . Flash can be seperated to two sections？ we need bootloader on the fly.

A： Yes! The F280045 and F280049 and F280049C, the 256KB versions of this family use two indpendent 128KB flash banks. So, it is possible to execute from one bank while programming the other. It can get a bit tricky, so good luck!

33 . If I add up 450ns and 1100 ns in the F28004x FCL time estimate, it is actually 1550 ns not 1.6 us. Why are you showingn 1.6us.

A： We are stating less than 1.6 us and we are being conservative (probably overly conservative) until we have our final quantification of the FCL algorithm on the F28004x. Those results should be made public in 1Q 2019.

34 . The time of “FOC processing and PWM Updated” is based on IQmath function? or FPU?

A：These are floating point algorithms taking strong advantage of the Trigonometirc Math Unit functions (sine, cos, sqrt) as well as the floating point min/max instructions. The FOC-only processing is estimated to be 1.1 us in period but that is a very conservative estimate. The F280049/9C have a 32-bit floating point unit as well as the 32-bit floating point CLA co-processor. 200 real time floating point MIPS optimized for power control! And available at a Piccolo family price point!

35 . What’s risk of using PGA for current sensing?

A： The programmable gain amplifiers are not precision amplifiers. For some precision servo control applications, they may not meet your spec. I encourage you to investigate them and decide for yourself if they are suitable for the performance of your application.

36 . How much does the F280049C cost?

A： The 1 KU web/resale price for the F280049CPMS is $6.85. This configuration includes both the InstaSPIN-FOC solution as well as the conffigurable logic block, control law accelerator and 256KB of flash.

37 . When will C2000 release the F280049 dual axis project in C2000Ware?

A： Thanks for asking! We plan for this to be part of the March 2019 release of the Motor Control Software Development Kit ( MC - SDK ). Since the F280049 is very similar to the F2837x in peripherals and CPU, you could start with the FCL-SFRA project in controlSUITE today for the '37x series and port today, if you need it sooner.

Look in this path: C:\ti\controlSUITE\libs\app_libs\motor_control\libs\FCL_SFRA

38 . Is it enough to make double - axis ECAT with SPI?

A： Our high speed SPI is 25 MHz and DMA supported so it can be very low latency and high bandwidth. I think this is more than what the SPI on the ET1100 can handle. So, if ET1100 can handle dual axes today, F28004x should be no problem.

39 . Isn’t there some PWM performance concern when using the immediate update mode like FCL does?

A： Not really. Since our carrier frequency is fixed, all that we are modulating is the duty cycle, or one compare register. So, you don’t need to worry about a synchronized update of multiple PWM registers. Shadow registers and global load are not necessary in the FCL case. What you are not able to do is update the PWM duty cycle while the FOC processing is taking place. This time where it cannot be updated does have an impact on the total modulation capability, or, the modulation index will be less than 100%. However, as stated during the presentation, when the loop processing time is sucha small part of the total carrier period, the impact on the modulatin index is very small. Our estimates for modulation index of FCL on the 100MHz F28004x series is 93.6% – still quite high!

40 . in order to achieve FCL, is there any limit at the total current loop execution time?

A： Longer execution times will have a bigger impact on the modulation index of the drive depending upon the PwM carrier frequency. Shorter loop times, like FCL, make double sampling practical and because of less latency in processing there is less time for the current to change from what was sampled and how the system subsequently responds.

41 . F28004x的instaspin什么时候发布？

A： Hello Jack - you can expect many new capabilities in March 2019 when our first Motor Control Software Developer’s Kit will be released. Sensorless support with InstaSPIN-FOC on Potenza will be part of the release as will the Fast Current Loop IP and tools, too!

42 . The ADC conversion time on the F28004x series is 290ns per the datasheet. Why are you showing 450ns in the presentation?

A： Good question. We are being conservative in our estimate since we have not yet released the project on the F28004x series of MCUs.

43 . is there any none TI chips support FSI

A： F28004x is the first device to support the Fast Serial Interface. All future devices from C2000 will include at least one TX and one RX FSI port (like F28004x) going forward.

44 . How many analog signals can be managed by F28004x MCU?

A： Depends upon the package selected but the 100 pin PZS package can support 28 analog signals not counting Vref pins. Recall that 21 of those signals can alternativel be used as general purpose “digital” inputs.

45 . the motor driver is open source?

A： Depending upon which motor control algorithm you are referring to, our current loop, speed loop, position loop and the supporting “chip level” software are made available in source code form in controlSUITE and soon to be included in our Motor Control Software Developent Kit (based on C2000Ware).

46 . C2000 piccolo和delfino是啥关系

A： Delfino是高性能系列，Piccolo是高性价比系列

47 . F28004系列的主频最高多少，存储空间多大？

A： 100MHz和256KB

48 . 低功耗能做到什么程度

A： 100mA左右