在电压模式下工作时，请问如何使用步进时钟模式？

对于PowerSTEP01，L6470和L6480，BEMF补偿不适用于步进时钟模式（电机状态停止）。通过改变PWM频率加速电机时，输出（电机）电压不会增加。没有BEMF补偿，输出电流在高速时太低。因此，步进时钟模式在电压模式下完全无用。
我有一个临时解决这个问题的方法，我设置KVAL_HOLD寄存器来改变速度时的电压。但SPI通信占用了很多CPU圈，因此速度有限，因为间隔不能低于SPI通信需求。菊花链更糟糕：总线上的设备越多，SPI通信消耗的时间就越多。因此，难以在两步脉冲之间改变电压。
还有一个问题：在SPI通信（设置KVAL_HOLD）结束（所有字节都是从MCU发送）之后，电压实际变化需要多长时间？我们必须保证在脉冲达到更高速率之前电压足够高，所以我认为这是一个重要的问题。如果不知道命令（设置参数）和实际执行的动作之间的经过时间，我们就无法估计出正确的引导（发送命令的时间）来满足条件。请问有人给我们答案吗？
或者，任何机构能否为我们提供更好的解决方案，以便在电压模式下使用步进时钟模式？恕我直言，使用RUN命令和速度配置文件无法完成步进时钟模式可以执行的所有操作。并且只有电压模式具有1/128微步。那么如何使步进时钟模式和电压模式组合工作对我来说很重要。
（我还没有尝试过当前模式，因为1/16微步对我的项目来说不够好。所以我不知道当前模式是否有类似问题。步进时钟模式在当前模式下工作得更好吗？如果有人知道，您可以在这里提供一些信息，其他人可以从您的知识和建议中获益。）
任何建议表示赞赏。谢谢。

#bemf＃powerstep01＃voltage-mode #step #compensation



以下为原文




With PowerSTEP01, L6470 and L6480, the BEMF compensation does not work with step-clock mode (the motor status is stop). The output (to motor) voltage won't be increased when speeding up the motor by changing PWM frequency. without BEMF compensation, the output current is too low at high speed. Thus, step-clock mode is totally useless in voltage mode.
I have a temporary solution for this problem, I set KVAL_HOLD register to change the voltage when changing speed. But the SPI communications eat many CPU circles, so there is a limitation of speed because the interval can't be less than a SPI communication needs. It is even worse with daisy chain: more devices on the bus, more time is consumed by SPI communications. So, changing voltage between two step pulses is difficult.
And there is a question: after the SPI communication (setting KVAL_HOLD) ends (all bytes are sent from MCU), how long does it take before the voltage is actually changed? we must guarantee the voltage is high enough before the pulses achieve a higher rate, so I think this is a important question. Without the knowledge about elapsed time between command (setting parameters) and action actually executed, we cannot estimate a proper lead (time to send the command) to satisfy the condition.  Could anybody give us an answer please ?
Or, Could any body give us a better solution to use step-clock mode in voltage mode? IMHO, using the RUN command and speed profiles can't do everything the step-clock mode can do. And only voltage mode has 1/128 micro-step. So how to make the combination of step-clock mode and voltage mode work is important to me.
(I haven't tried current mode yet, because the 1/16 micro-step is not good enough for my project. So I don't know if current mode have similar problems. Does step-clock mode work better in current mode?  If somebody know, you may provide some info here, others can get benefits from your knowledge and advice.).
Any suggestions is appreciated. Thank you.

#bemf #powerstep01 #voltage-mode #step #compensation