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I am currently developing a small robot project. The motor driver I have uses a L298 motor driver IC. It supports two methods of control, PWM and PLL and it is configurable with on-board jumpers on my board. What is the difference between the two in motor control? I understand how PWM works, but PLL got me thinking. Should I consider PLL?

For reference, it seems that they work in the same way: http://www.dfrobot.com/wiki/index.php?title=Arduino_Motor_Shield_(L298N)_(SKU:DRI0009)#Sample_Code

Also, here is the L298 datasheet, but it doesn't mention anything about PLL: http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00000240.pdf

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This answer isn't correct. f.e. L298 motor shiled has PWM and PLL too. look at L298 wiki. Main difference is that with PLL you controlling speed and direction at one pin from -255 to 255 and second pin HIGH/LOW sets only enable/disable motor (you must switch pins as wiki says). With PWM you controlling speed with one pin and direction with second pin.

For me PLL works better than PWM, where I had problems that one of motor starts later.

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  • \$\begingroup\$ There is no PLL mode because the board does not have any parts needed for a PLL. \$\endgroup\$ – W5VO Nov 17 '13 at 8:04
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There is no Phase Locked Loop (PLL) on that board, and I can't think of any other "PLL" that could possibly apply. Looking at the schematic, the "PLL" mode that is described in the wiki you linked to is just swapping the enable and direction pins. That's it.

You can see that this is all that those jumpers do by looking at the example code. Notice how the only difference between the two programs is lines 2-5. The only difference is that the enable and motor pin numbers have different values.

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  • \$\begingroup\$ I'm so disappointed right now :P Why would they do that? On their other boards they also include jumpers that switch between microcontroller pins, but it's always obvious. \$\endgroup\$ – giannoug Jun 19 '13 at 22:20

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