# GM862-GPS RS232 Eval board connection problem

**URL:** <https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700>\
**Category:** Development Boards\
**Created:** [March 9, 2008, 7:30pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700 "2008-03-09T19:30:08Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![mbeltagy](https://avatars.discourse-cdn.com/v4/letter/m/d2c977/32.png) [@mbeltagy](https://community.sparkfun.com/u/mbeltagy)\
**Post date:** [March 9, 2008, 7:30pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/1 "2008-03-09T19:30:08Z")

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I am currently trying to interface the GM862-GPS RS232 eval board with the Atmel STK500 starter kit.

The module works fine when it is connected to the PC (using hyperterminal).

I wrote a code on the microntroller using the rprintf function from the avr library to dial a number but it does not work

I tested the code by connecting the microcontroller kit to another PC and it displays the correct command on hyperterminal.

Any help would be appreciated

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**Author:** ![leon\_heller](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/leon_heller/32/7602_2.png) [@leon\_heller](https://community.sparkfun.com/u/leon_heller)\
**Post date:** [March 9, 2008, 7:48pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/2 "2008-03-09T19:48:57Z")

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Have you tried connecting the AVR to the PC via a level converter, to make sure that your serial routines are working properly?

Leon

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<div class="post-metadata">

**Author:** ![mbeltagy](https://avatars.discourse-cdn.com/v4/letter/m/d2c977/32.png) [@mbeltagy](https://community.sparkfun.com/u/mbeltagy)\
**Post date:** [March 9, 2008, 8:32pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/3 "2008-03-09T20:32:42Z")

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I connected the AVR using the starter kit to the PC directly without a level converter and it worked fine

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<div class="post-metadata">

**Author:** ![mbeltagy](https://avatars.discourse-cdn.com/v4/letter/m/d2c977/32.png) [@mbeltagy](https://community.sparkfun.com/u/mbeltagy)\
**Post date:** [March 9, 2008, 8:44pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/4 "2008-03-09T20:44:44Z")

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Thank you very much leon.

It actually did work after swapping the TxD and RxD

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**Author:** ![leon\_heller](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/leon_heller/32/7602_2.png) [@leon\_heller](https://community.sparkfun.com/u/leon_heller)\
**Post date:** [March 9, 2008, 9:30pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/5 "2008-03-09T21:30:32Z")

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That caught me out once with a GE-863, I had to cut a couple of tracks on my PCB. ☹

Leon

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**Author:** ![maokh](https://avatars.discourse-cdn.com/v4/letter/m/9de053/32.png) [@maokh](https://community.sparkfun.com/u/maokh)\
**Post date:** [March 10, 2008, 9:52pm UTC](https://community.sparkfun.com/t/gm862-gps-rs232-eval-board-connection-problem/6700/6 "2008-03-10T21:52:37Z")

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…at least you didnt forget to read the little note about SIRF\_BIN and the second serial port 😉