Serial reading issue(Corrupted input serial packets)

[yarsanich]

Following the first implementation of the microbit hub software, serial reading should be implemented by each byte.

Here dapjs was used for serial reading(https://github.com/Taylor-Woodcock/microbit-web-bridge/blob/master/public/javascripts/SerialHandler.ts#L38). dapjs serial reading implemented using clock approach(https://github.com/ARMmbed/dapjs/blob/master/src/daplink/index.ts#

Hub microbit produce messages regarding SLIP_* characters that have been used for writing to serial here.

If we start monitoring serial port we can see next

RAW webusb log
Received: ��/share/historicalData/0tnw3glcelsiuss��hare/hist
WebBridge.bundle.js:5261 Received: �ՂDATA SENT�lsius�nw3glcelsiuss�celsiuss��
WebBridge.bundle.js:5261 Received: �ik/share/historicalData/0tnw3glcelsiuss�lcelsius
WebBridge.bundle.js:5261 Received: �lc��SENT�oricalData/10tnw3glcelsius���/sha
WebBridge.bundle.js:5261 Received: �ik�DATA SENT�3glcelsiuss�^/share/historicalData/
WebBridge.bundle.js:5261 Received: ��/share/historicalData/0tnw3glcelsiuss��hare/hist
WebBridge.bundle.js:5261 Received: �ՂDATA SENT�lsius�nw3glcelsiuss�celsiuss��
WebBridge.bundle.js:5261 Received: �ik/share/historicalData/0tnw3glcelsiuss�lcelsius
WebBridge.bundle.js:5261 Received: �lc��SENT�oricalData/10tnw3glcelsius���/sha
WebBridge.bundle.js:5261 Received: �ik�DATA SENT�3glcelsiuss�^/share/historicalData/
WebBridge.bundle.js:5261 Received: ��/share/historicalData/0tnw3glcelsiuss��hare/hist
WebBridge.bundle.js:5261 Received: �ՂDATA SENT�lsius�nw3glcelsiuss�celsiuss��
WebBridge.bundle.js:5261 Received: �ik/share/historicalData/0tnw3glcelsiuss�lcelsius
WebBridge.bundle.js:5261 Received: �lc��SENT�oricalData/10tnw3glcelsius���/sha
WebBridge.bundle.js:5261 Received: �ik�DATA SENT�3glcelsiuss�^/share/historicalData/
WebBridge.bundle.js:5261 Received: ��/share/historicalData/0tnw3glcelsiuss��hare/hist
WebBridge.bundle.js:5261 Received: �ՂDATA SENT�lsius�nw3glcelsiuss�celsiuss��
WebBridge.bundle.js:5261 Received: �ik/share/historicalData/0tnw3glcelsiuss�lcelsius
WebBridge.bundle.js:5261 Received: �4�(/share/historicalData/9tnw3glcelsiuss����/sha

oricalData/28tnw7glcelsiussÀï./share/historicalDat - serial packet after dapJS.

[taylow]

Thanks for posting the issue. It'll be good to have all of this in one place.

As for the implementation of a byte-by-byte read, I have looked into DAPLink's commands and have yet to find a single byte read. It appears DAPjs is sending the value 0x83 (READ) during the timer found at startSerialRead(). I was hoping there would be a similar value for reading a single byte.

I understand you have some alternate approaches than DAPjs. It will be interesting to see what you come up with.

[taylow]

Actually, just thinking bout it, has anyone tried changing the serialDelay parameter passed into startSerialRead()? I'm wondering if slowing the timer in which the data is read would help as the data may be being processed before all data is available?

Another possible solution is that we implement the SLIP_* fully so that each command has a start and an end character. This way, we can fill a buffer with the incoming data until a SLIP_END character is found.

This would be as simple as appending the data to a buffer and only emitting the DAPLink.EVENT_SERIAL_DATA event when the buffer contains both the start and end characters.

[yarsanich]

@Taylor-Woodcock I tried lowering serial_delay value, but no-luck.

[yarsanich]

@Taylor-Woodcock your second suggestion is possible, but we need to fork dapJS then.

[yarsanich]

Received to write: ���^���DATA SENT�
WebBridge.bundle.js:5261 Received: ���^���DATA SENT�oricalData/�3�tnw3�gl�celsius���7�tnw3

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