Timeline for UART signal distortion with AVR
Current License: CC BY-SA 3.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 19, 2011 at 8:33 | vote | accept | sum1stolemyname | ||
| Dec 8, 2011 at 16:56 | comment | added | Chris Stratton | @sum1stolemyname By changing the oversampling from 16x to 8x you can get 111111 baud which is a lot closer than 125000 baud and often works - updated my answer below to be more explicit about this. | |
| Dec 8, 2011 at 8:02 | history | edited | sum1stolemyname | CC BY-SA 3.0 |
fixed a typo, edited information
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| Dec 7, 2011 at 17:23 | history | tweeted | twitter.com/#!/StackElectronix/status/144467156548067328 | ||
| Dec 7, 2011 at 17:23 | answer | added | Chris Stratton | timeline score: 7 | |
| Dec 7, 2011 at 13:12 | comment | added | Olin Lathrop | It does look like capacitive coupling at first glance, but look closely and you'll see the voltage is actually drifting in the wrong direction. The DC bias should have moved up during the pulses, not down if the signal were capacitively coupled. I'm suspecting this has more to do with power supply droop. I can see these are not the RS-232 levels, but is there possible a charge pump supply in there somewhere? | |
| Dec 7, 2011 at 12:26 | comment | added | Russell McMahon♦ | Are these consistent?. May be : "uart pins are directly connected to the communication link" and The other microcontroller UART is connected to a four channel multiplexer, and it is possible to select ... which of the four new UARTs is required to connect to the UART on the microcontroller. four new UARTs are connected as follows. One is connected to the GPRS board, the other to the GPS and the other two are accessible to the user in the auxiliary I2C – UART connector. Multiplexer configuration is carried out using: { setMuxAux1(); setMuxAux2(); setMuxGPS(); setMuxGPRS() } | |
| Dec 7, 2011 at 10:49 | history | edited | sum1stolemyname | CC BY-SA 3.0 |
added 245 characters in body
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| Dec 7, 2011 at 10:32 | answer | added | Russell McMahon♦ | timeline score: 3 | |
| Dec 7, 2011 at 10:09 | comment | added | kenny | 60hz hum with some 50 mixed in sounds kind of sexy. ;) | |
| Dec 7, 2011 at 10:08 | comment | added | Russell McMahon♦ | @Majenko - Apearance is sikilar but timing seems to make sense only if he's got 500 Hz mains at 50Hz :-). 100 uS/division = 1 mS across screen and looks like about 1/2 cycle so 2 mS/cycle = 500 Hz. BUT scope may be displaying and image based on multiple cycles | |
| Dec 7, 2011 at 10:07 | history | edited | sum1stolemyname | CC BY-SA 3.0 |
updated information on what i am sending
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| Dec 7, 2011 at 9:26 | comment | added | Majenko | That looks almost like the ever present 50/60Hz hum that pervades the universe these days. Check your grounding. | |
| Dec 7, 2011 at 8:58 | history | asked | sum1stolemyname | CC BY-SA 3.0 |