# Difficulty decoding Manchester code

**URL:** https://discuss.saleae.com/t/difficulty-decoding-manchester-code/2529
**Category:** Support
**Created:** [November 6, 2023, 2:22pm UTC](https://discuss.saleae.com/t/difficulty-decoding-manchester-code/2529 "2023-11-06T14:22:45Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![cs.thompson](https://avatars.discourse-cdn.com/v4/letter/c/ed8c4c/32.png) [@cs.thompson](https://discuss.saleae.com/u/cs.thompson)
#### Post date: [November 6, 2023, 2:22pm UTC](https://discuss.saleae.com/t/difficulty-decoding-manchester-code/2529/1 "2023-11-06T14:22:45Z")

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Very short story… I have an SI4438 chip, which takes data from a GPIO pin to then sends out RF. I’m trying to decode that GPIO data, which appears to be manchester encoding and I’m getting close, but still can’t get the data properly decoded. Here’s a snip:

 ![image](https://canada1.discourse-cdn.com/flex030/uploads/saleae/original/2X/1/1eb85178b31c7c7e0dfb6427009ec66548ff236e.png)

The preamble should be 01010101, so it appears that the timing is correct since it seems that I’m getting the bits properly.

Any suggestions on how I can get a better decode?

SAL file attached, the data I am looking at is on Channel 6.  
[Sendcommand.sal](https://discuss.saleae.com/uploads/short-url/3jzFSDbXPn9YB4jD62BSsiKIY20.sal) (15.5 KB)

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### Author: ![timreyes](https://yyz2.discourse-cdn.com/flex030/user_avatar/discuss.saleae.com/timreyes/32/108_2.png) [@timreyes](https://discuss.saleae.com/u/timreyes)
#### Post date: [November 8, 2023, 10:19pm UTC](https://discuss.saleae.com/t/difficulty-decoding-manchester-code/2529/2 "2023-11-08T22:19:18Z")

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Thanks for sending over your capture file. I took a quick measure of your signal’s frequency as per the image below.

 ![Screenshot 2023-11-08 at 4.15.15 PM](https://canada1.discourse-cdn.com/flex030/uploads/saleae/original/2X/4/4675f3d592cd1901b0c5dde522cf26890442a0a2.png)

I measured it to be approximately 1.824 kHz and modified the Manchester settings in your capture file accordingly.

Here is the resulting preamble with the new settings, which gets you closer to what you expected.

 ![Screenshot 2023-11-08 at 4.17.15 PM](https://canada1.discourse-cdn.com/flex030/uploads/saleae/original/2X/0/091705a7fc20e9b4a32e27f99914ff51a1242cea.png)

Here is the modified capture file as well.  
[TR-Sendcommand.sal](https://discuss.saleae.com/uploads/short-url/kfU7YMloNHw1WANQy3eBDBsvTOW.sal) (15.0 KB)

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### Author: ![delacruz.garcia.artu](https://avatars.discourse-cdn.com/v4/letter/d/8c91f0/32.png) [@delacruz.garcia.artu](https://discuss.saleae.com/u/delacruz.garcia.artu)
#### Post date: [January 8, 2024, 7:02pm UTC](https://discuss.saleae.com/t/difficulty-decoding-manchester-code/2529/3 "2024-01-08T19:02:21Z")

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Hi cs.thompson. Were you able to solve the problem? I have a similar problem.