# RCM4400W pwm problems.

**URL:** <https://forums.digi.com/t/rcm4400w-pwm-problems/9228>\
**Category:** Rabbit\
**Created:** [July 24, 2007, 10:50am UTC](https://forums.digi.com/t/rcm4400w-pwm-problems/9228 "2007-07-24T10:50:59Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![dg040568](https://avatars.discourse-cdn.com/v4/letter/d/c67d28/32.png) [@dg040568](https://forums.digi.com/u/dg040568)\
**Post date:** [July 24, 2007, 10:50am UTC](https://forums.digi.com/t/rcm4400w-pwm-problems/9228/1 "2007-07-24T10:50:59Z")

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I am trying to use the following port pins for PWM output on an RCM4400W module

PWM 0 : PC4  
PWM 1 : PC5  
PWM 2 : PE6  
PWM 3 : PE7

PWM outputs appear for channels 0, 1 and 3 but PWM2 on PE6 is just noise.  
After reviewing the schematics and documentation for the RCM4400W I can see that PE6 does not come out to the connector (JP1 pin 38) unless jumper 1 has pins 1 - 2 connected together.

The problem is that this will also connect the signal CS\_FPGA (chip select for the FPGA) to JP1 pin 38 as well.

Does anyone know if driving a PWM output on PE6 will adversely affect the FPGA by driving it’s chipselect line up and down ?

Darran.