# HLA monitoring two sources **URL:** \ **Category:** Extensions\ **Created:** [May 26, 2021, 12:18am UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044 "2021-05-26T00:18:08Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![colin](https://avatars.discourse-cdn.com/v4/letter/c/e19b73/32.png) [@colin](https://discuss.saleae.com/u/colin)\ **Post date:** [May 26, 2021, 12:18am UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/1 "2021-05-26T00:18:08Z")
Hi. Had a Logic8 for about 30mins so far and love it! Wow. I would like to write an HLA that monitors two (AsyncSerial) sources. It would monitor the master and slave comms of a serial bus. I see how easy it is to write a python HLA monitoring one side, but is it possible to get an AnalyzerFrame from each channel so I can check for bus sync issues? Sure, I could instantiate the HLA twice and monitor each channel individually, but it doesnt allow me to verify the slave response is valid given the master request. If this isn’t supported yet, perhaps a suggested implementation might be to detect how many AnalyzerFrame arguments are in the decode(…) function, so for example this decode method: ```python def decode(self, ch1_frame: AnalyzerFrame, ch2_frame: AnalyzerFrame): ``` The settings window would reflect the decode method and see two AnalyzerFrame args so populate the settings window with two source channel selectors. ---
**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:** [May 26, 2021, 12:27am UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/2 "2021-05-26T00:27:59Z")
Hi @colin - This is unfortunately not possible right now. In the meantime, i went ahead and added your feature request in an idea post below: [https://ideas.saleae.com/b/feature-requests/allow-hla-to-monitor-multiple-lla-inputs](https://ideas.saleae.com/b/feature-requests/allow-hla-to-monitor-multiple-lla-inputs) We’ll continue tracking for interest in this in the post above and will take your decode() definition into account once I discuss this with the team here. ---
**Author:** ![colin](https://avatars.discourse-cdn.com/v4/letter/c/e19b73/32.png) [@colin](https://discuss.saleae.com/u/colin)\ **Post date:** [May 26, 2021, 1:32am UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/3 "2021-05-26T01:32:53Z")
I just saw the existing Idea for this: > **[Multiple inputs to HLAs - Logic 2 - Ideas and Feature Requests - Saleae](https://ideas.saleae.com/b/feature-requests/multiple-inputs-to-hlas/)** > > Currently HLAs only accept input from one analyzer. For some use-cases, taking input from multiple analyzers is necessary. You can therefor delete the new entry you made in Ideas. Sorry, didnt see the other post here until now: > [@Extension output message format](https://discuss.saleae.com/t/extension-output-message-format/1021/6): > > Thank you Tim actually my idea would have been to provide the output of the first analyzer to the second analyzer too (as well as to Logic 2), so that I can already perform some low -level analysis in the “layer 2” analyzer and then provide the decoded packets to the second one for further processing. In this way i can actually simulate a device that receives the packets. The way I then represent the different layers would be independent from each other. ---
**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:** [May 27, 2021, 6:03pm UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/4 "2021-05-27T18:03:33Z")
@colin Thanks for pointing that out! I went ahead and merged them both together. ---
**Author:** ![sam.kovnar](https://avatars.discourse-cdn.com/v4/letter/s/90db22/32.png) [@sam.kovnar](https://discuss.saleae.com/u/sam.kovnar)\ **Post date:** [June 9, 2021, 2:20pm UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/5 "2021-06-09T14:20:57Z")
I also had this issue. I’ve been using sockets to connect the two HLAs and let them communicate with each other, but it’s been a bit finnicky getting the timing right. ---
**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:** [June 9, 2021, 9:36pm UTC](https://discuss.saleae.com/t/hla-monitoring-two-sources/1044/6 "2021-06-09T21:36:31Z")
@sam.kovnar Oh wow, that’s great you’ve been able to get something working, albeit being finnicky. Would you mind letting me know what kind of data you are trying to get out of your capture, and how your software, analyzers, and hardware are set up? I’d love to understand your use case a bit more.