Can Be Closed in favor of #6272 -- HardwareSerial: make begin() virtual #6176
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…ng it in subclasses where needed
How does this work exactly? Same UART, but different Pins in different tasks? |
Yes, for example I have a project where I need to initially program a small ATTiny MCU on the same board via UPDI (using UART), but then I do not need to use it again, whereas I can use the UART, especially in ESP32-S2/ESP32-C3 cases for different purposes. |
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But what is preventing you now? Just reinit with new pins once done with the ATTiny? |
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cc @SuGlider |
Currently we can do that via Serial.begin() by passing the new pins and all would be well if no-one after that would happen to call begin() again while we're doing what we need to do... In a lot of cases, however, (UPDI programming library comes to mind), the libraries in use would simply do Serial.begin() multiple times. The current implementation of HardwareSerial does not like that - it falls back to the default pins for the given UART and things break miserably... :-) since I can imagine other people relying on this functionality and I wouldn't want to mess with it, I would simply prefer to be able to subclass HardwareSerial and implement the handling of persistent different pins there. If the above wasn't clear enough: If I call Serial.begin(115200, SERIAL_8N1, x, y) for example - everything will be fine and Serial will start working on rxPin x and txPin y. Unfortunately this will be true only until someone (e.g., in a library) needs to switch, say, the baud rate and does: |
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@SuGlider wasn't this fixed? There should be a way to do this without resorting to new classes and implementations. We already have this in @sgalabov I think we should actually make Serial not reassign pins if they are not specifically set. |
@me-no-dev, something like the last commit? :-) |
| if(_uart_nr == 1 && rxPin < 0 && txPin < 0) { | ||
| rxPin = RX1; | ||
| txPin = TX1; | ||
| if(_uart_nr == 1) { |
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those do the same exact thing as before :) reassign the pins if they are not -1
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Nope, they assign to the _rxPin and _txPin, which are now protected members of the class, so they persist.
They are now only changed in begin() if:
- rxPin parameter is > -1 -> we take its value as the _rxPin value
- txPin parameter is > -1 -> we take its value as the _txPin value
Then later, if any of the _rxPin/_txPin is still -1 we take the defaults.
This allows us to only override the already assigned pins where actually needed I believe..
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@sgalabov @me-no-dev Does it sound good for you guys? |
Fine with me, thanks. :-) |
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@SuGlider I could have sworn that we discussed this and it has been already implemented :D |
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This PR will be replaced by #6272 |
SuGlider
changed the title
Make HardwareSerial's begin() method virtual, so that subclasses are able to override it where needed.
This is useful for example when we want to re-use the same uart with different RX/TX pin pairs for different tasks.