tag:blogger.com,1999:blog-5983110881018172452.post6960316883926364588..comments2023-03-25T02:55:49.760-06:00Comments on Bot Thoughts: Diagnosing a Broken OscilloscopeMike Shimniokhttp://www.blogger.com/profile/17602015624941667574noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-5983110881018172452.post-33022508499031914552016-08-15T22:05:59.803-06:002016-08-15T22:05:59.803-06:00How to fix non working vertical scale vpp..How to fix non working vertical scale vpp..Xentralishttps://www.blogger.com/profile/04111750104304486064noreply@blogger.comtag:blogger.com,1999:blog-5983110881018172452.post-45977821523116332142015-12-20T19:35:57.175-07:002015-12-20T19:35:57.175-07:00I have an unit of this scope it has a problem that...I have an unit of this scope it has a problem that looks like this,was that small battery 3v.A feira: vendo e troco!!!https://www.blogger.com/profile/02611120187120369462noreply@blogger.comtag:blogger.com,1999:blog-5983110881018172452.post-59051155346431044342014-02-01T10:18:03.801-07:002014-02-01T10:18:03.801-07:00I've had a TV do this, but in that case four b...I've had a TV do this, but in that case four buttons were arranged to put different resistors in circuit to form a voltage divider and the microcontroller analog input was drawing a bit too much current causing incorrect or phantom button pushes. Lowering all the resistances was only a temporary fix.Jimhttps://www.blogger.com/profile/05246205767574128987noreply@blogger.comtag:blogger.com,1999:blog-5983110881018172452.post-69344264563172660832014-01-31T14:52:10.484-07:002014-01-31T14:52:10.484-07:00Thanks for the help. Would be great to talk more i...Thanks for the help. Would be great to talk more in email if you want, to make sure I'm not missing something. <br /><br />I had hoped for an issue outside the MCU. However the key polling signals come in strong and correct at the MCU pins but the MCU acts like a different (default?) button was pressed. Like the MCU isn't detecting the polling signal.<br /><br />I noticed after posting that this behavior is intermittent, though. I can get it to recognize the correct button press every once in awhile.<br /><br />Also just FYI, the Saleae CH3 shows the signal coming back in on one of the P lines (CH3) from polling the K lines (CH4-6). I tested on all the P lines--by connecting probes to the MCU's pins. The signals are correctly making it all the way to those pins.Mike Shimniokhttps://www.blogger.com/profile/17602015624941667574noreply@blogger.comtag:blogger.com,1999:blog-5983110881018172452.post-88284225870132057282014-01-31T04:14:16.104-07:002014-01-31T04:14:16.104-07:00Hmmm. I suspect from what you've said that the...Hmmm. I suspect from what you've said that the P0 and P3 lines are shorted together somewhere. It's fairly consistently reading the corresponding button on P3 when you press any button on P0, which is more likely to be the result of a short somewhere in the circuit than a fault in the MCU. (Also, the waveform you've captured with Saleae Logic looks fishy; are Channel 3 and Channel 4 meant to be connected to the same key matrix pin?)makomkhttps://www.blogger.com/profile/00266600558871564196noreply@blogger.com