# how to use the serial E?

**URL:** <https://forums.digi.com/t/how-to-use-the-serial-e/13301>\
**Category:** Rabbit Software\
**Tags:** e, rcm6760-serial\
**Created:** [July 11, 2014, 8:42am UTC](https://forums.digi.com/t/how-to-use-the-serial-e/13301 "2014-07-11T08:42:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![huanghao](https://avatars.discourse-cdn.com/v4/letter/h/e5b9ba/32.png) [@huanghao](https://forums.digi.com/u/huanghao)\
**Post date:** [July 11, 2014, 8:42am UTC](https://forums.digi.com/t/how-to-use-the-serial-e/13301/1 "2014-07-11T08:42:11Z")

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when i debug the serial E,I define the macros before the main function.  
#define SERE\_TXP0RT PEDR  
#define SERE\_RXPORT PEDR // Defaults to PCDR  
#define EINBUFSIZE 31  
#define EOUTBUFSIZE 31

but it also have the problem that conflict with the programming port in debug mode.why?  
my source code:  
void main(void)  
{  
serEopen(BAUDRATE);  
while(1)  
{  
serEputc(0x55);  
}  
}

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<div class="post-metadata">

**Author:** ![developer](https://avatars.discourse-cdn.com/v4/letter/d/bcef8e/32.png) [@developer](https://forums.digi.com/u/developer)\
**Post date:** [July 12, 2014, 5:24pm UTC](https://forums.digi.com/t/how-to-use-the-serial-e/13301/2 "2014-07-12T17:24:51Z")

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To use serial port E, there are samples. I only know the rs485 sample in the dc 9.62 package, but I am sure that sample carries over to 10.x. I use the programmer’s port on the 3k and serial E without a problem. You have to toggle transmit and receive for it to work right.

Like I said, check the samples and you will see how to do it. You can also set more than the speed (i.e. data format, etc).