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I'm trying to generate a quadrature signal with a L297 http://www.st.com/content/ccc/resource/technical/document/datasheet/f9/35/6e/3f/48/18/48/51/CD00000063.pdf/files/CD00000063.pdf/jcr:content/translations/en.CD00000063.pdf I use only phase A and C in order to have a 90° offset

Here is my wiring:
// L297 -> MCU
2 GND -> GND
4 A -> read out phase A
7 C -> read out phase C
10 ENABLE -> GPIO Pin 1
12 Vs - +5v
11 Control -> GPIO Pin 5 set to high for phases line ABCD
17 CW/CCW -> GPIO Pin 2 set to high or low depeding the direction
18 Clock -> GPIO Pin 3
19 Half/Full -> GPIO Pin 6 set to low for full step
20 RST -> +5v

According to my understanding, when I want the L297 to run, I write a bit on GPIO Pin 1 (HIGH) to enable the L297 For changing direction, I must put Pin 2 High or Low And when I want to send a pulse, I write a bit on Pin 3 /Clock i'm sending pulse to clock but channel A and C stay always low. Do you have any idea of what could go wrong with my wiring ? or with my understanding ?

Thank you

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  • \$\begingroup\$ Are you simply setting the clock line high each step, or are you remembering to actually produce a pulse? \$\endgroup\$ – WhatRoughBeast Sep 11 '17 at 0:18
  • \$\begingroup\$ I set alternatively the pin HIGH then LOW then High etc \$\endgroup\$ – vib Sep 11 '17 at 3:46
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If you don't have current sense R to ground, and a Vref on p15 , a floating input that exceeds Vref p15 which is also floating, it will reset the outputs.

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  • \$\begingroup\$ OK I put 2v (randomly choose between 0 and 3v) on Vref. What should I do with this part of your comment " current sense R to ground"? \$\endgroup\$ – vib Sep 11 '17 at 3:49
  • \$\begingroup\$ 0V or a resistor to ground \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 11 '17 at 4:39
  • \$\begingroup\$ but connected to what? \$\endgroup\$ – vib Sep 11 '17 at 5:05
  • \$\begingroup\$ look at the IC schematic and you will see these pins on a comparator. It is supposed to sense motor current and shutoff when > Vref \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 11 '17 at 5:18
  • \$\begingroup\$ Ok, thank you I connected both SENS1 and 2 to ground, Vref with 2v but I have the same result, my counter is still going up very quickly and never stop. I don't know what 'im doing wrong \$\endgroup\$ – vib Sep 11 '17 at 5:23

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