Timeline for Arduino and HC-05 hardware serial issues
Current License: CC BY-SA 3.0
19 events
| when toggle format | what | by | license | comment | |
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| Jul 13, 2015 at 7:11 | comment | added | Bim | No sweat. I've got it hooked up via USB-Serial atm. I took a look at the CSR toolchain. Are you using the BlueCore SDK for this? If yes, in case you have sources I can compile, I could give it a shot too... That said, flashing the firmware seems to be the hard step. What would you recommend? I found this, which suggest using an Arduino as an SPI programmer. Sadly I have no access to a proper LPT port or FTDI232L atm. | |
| Jul 11, 2015 at 2:40 | comment | added | Mlagma | @Bim I'll throw some stuff together tomorrow. I didn't get a chance to do so today. | |
| Jul 10, 2015 at 7:28 | comment | added | Bim | I can run the Arduino at 250k and 500k Baud and it still works via standard serial, thus switching the HC-05 to those Baud rates might be a solution. Could you point me to a firmware/page that does this? I have already searched but not really found anything useful... | |
| Jul 10, 2015 at 3:18 | comment | added | Mlagma | Well this is really irritating. The signals look fine, so I doubt there are any problems left there. Another thing I can think of is in regard to the BAUD rate. The 16MHz crystal doesn't play too well with standard baud rates (even 115200 is a little off). However, multiples of 250k may work for you. The Arduino can deal with these speeds (others have done this). The HC-05 can also handle this, but it requires flashing it with different firmware. | |
| Jul 9, 2015 at 21:33 | comment | added | Bim | I captures the signals on the HC-05 TX line at 230400 Baud before and after the level converter now. Images here. The upper image is without a pull-up. The lower image is with a ~1.5kOhm pull-up from 5V to the RX pin of the Arduino (behind the level-converter). It looks like the signal should be fine with the pull-up... It could still be that the bit rates of the HC-05 and Arduino are not matching as Chris Stratton mentioned. In that case I guess I'm lost? | |
| Jun 16, 2015 at 13:39 | comment | added | Bim | I found this which suggest what you said (level-shifter distorts signal). I'll attach a probe and check the input/output signals of the level converter. I tried a pull-up resistor on the arduino side, but that didn't help. Will try one on the HC-05 side too... | |
| Jun 15, 2015 at 21:02 | comment | added | Mlagma | @Bim I didn't notice the links before. They definitely look distorted, and it also looks like they only go up to 4V (which is fine, I was just expecting a little less than 5V). In any case, it could be, like you said, there isn't enough time for the Arduino to register the logic high signal being that it takes a while to pass the threshold. You could try a pull up resistor, but the trade off is a longer fall time. Also, the level converter could be messing with the high frequencies, which can cause what you're seeing. If you really want, you could generate a sine wave and watch the response. | |
| Jun 15, 2015 at 7:48 | comment | added | Bim | See my previous reply that has screenshots of the signals linked. I grabbed the signals on the Arduino RX/TX pins so they are "behind" the level converter in relation to the HC-05. The TX signal from the HC-05 (RX on the Arduino) looks a bit distorted to me... They time the signal is HIGH might not be long enough for the Arduino. | |
| Jun 14, 2015 at 19:50 | comment | added | Mlagma | @Bim One thing that might be worth checking is the signal after the level converter. The part you bought said its used for I2C, and 115200 BAUD is around the standard I2C frequency. When you double it, the signal might be attenuated you're nearing the crossover point of the frequency response. | |
| Jun 11, 2015 at 7:31 | comment | added | Bim | A problem in the code could be that FastLED takes a lot of time in "show()" and due to that the serial port is overrun and data dropped... But at some point the code should recover. I uncommented the "while (Serial.available() > 0) { Serial.read(); }" loop (Line #83 in the sketch) to make sure incomplete data is consumed and the code will "sync" again, but that didn't help. It seems the other baud rates above 115200 the HC-05 supports are all not compatible with the (16MHz) Arduino... :( | |
| Jun 11, 2015 at 7:12 | comment | added | Bim | Yes.It is working at 115200 Baud in both directions. I captured the waveforms of a bit for 115200 and 230400. The signal generated by the Arduino looks good, but that of the HC-05 is pretty crappy: 115200 230400 | |
| Jun 10, 2015 at 22:27 | comment | added | Mlagma | @Bim Just to be sure, it is working now in both directions at 115200 Baud? The problem is that 230400 isn't working? | |
| Jun 10, 2015 at 13:34 | comment | added | Bim | The parts have arrived and I tried connecting the HC-05 to the Arduino Pro through the level-converter. The voltage levels are now around 4.5V. It all works well through bluetooth at 115200 Baud, but not at 230400 Baud.I also tried using a Arduino Due instead and connecting the HC-05 directly (TX0/RX0). As before, I can receive data on the PC side (The "Ada" status message), but no data arrives on the Arduino side... I'm at loss what to try to get higher throughput through the HC-05... | |
| Jun 2, 2015 at 11:08 | comment | added | Bim | Thanks a lot! I don't have a TL272 (or other OpAmps) at hand and don't really want to build a level shifter for 3 channels (RX/TX/EN) right now, so I ordered a bi-directional 4-Channel level shifter board. I still have a 3.3V linear regulator lying around. I seem to have broken the EN/KEY pin of the HC-05, but have a working one for 3.3V. It should take a couple of days for the stuff to arrive and for me to try things out, but then I'll get back with the results... | |
| Jun 1, 2015 at 21:20 | comment | added | Mlagma | @Bim I added some suggestions | |
| Jun 1, 2015 at 21:20 | history | edited | Mlagma | CC BY-SA 3.0 | added 1081 characters in body |
| Jun 1, 2015 at 20:23 | comment | added | Bim | DAMN! You seem to be right! The HC-05 puts out ~3V on its TX line. The RX line shows a maximum of 3.8V. What can I do? | |
| Jun 1, 2015 at 18:37 | review | First posts | |||
| Jun 2, 2015 at 1:01 | |||||
| Jun 1, 2015 at 18:35 | history | answered | Mlagma | CC BY-SA 3.0 |