# I/O problem with networking

**URL:** <https://forums.digi.com/t/i-o-problem-with-networking/10840>\
**Category:** Rabbit\
**Created:** [November 4, 2009, 4:47pm UTC](https://forums.digi.com/t/i-o-problem-with-networking/10840 "2009-11-04T16:47:24Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![RonH](https://avatars.discourse-cdn.com/v4/letter/r/bcef8e/32.png) [@RonH](https://forums.digi.com/u/RonH)\
**Post date:** [November 4, 2009, 4:47pm UTC](https://forums.digi.com/t/i-o-problem-with-networking/10840/1 "2009-11-04T16:47:24Z")

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I have a prototype board that I’m porting code (adding new features as well) to (using UCOS II on a RCM3000a), I have 8 LEDs hanging off a 74HC373 on I3(0x6000) , one of the outputs is a heartbeat and it works great until I add the TCP task then things go haywire, it looks like something else is overwriting the port, the heartbeat still flashes but most of the other LED’s flicker.  
I commented out function calls to see what was causing the problem and came down to 2 functions.  
MODBUS\_TCP\_tick()  
UDPDL\_Tick()

Something in these 2 function calls are causing my issue. I was wondering if anyone else has had an issue like this before and can save me the trouble of going through the huge TCP lib.

Ron