Audio (voice) - Stock 9X PCB

[flybabo]

Are you talking about MegaSound or the stock 9x mainboard?

On the MegaSound AVCC, AREF and VCC were all connected together. I now uncoupled AVCC and VCC, adding the choke and a cap (to GND). I also moved AREF to AVCC, but now I'm confused - should I keep it as is, or should I tie it to GND?

Sorry about confusing you - I assumed that the Megasound firmware would use the same ADC function as er9x firmware
if we ever add any analog inputs to the sound board.
er9x firmware selects the AVCC signal as the voltage reference through an internal passive switch not through the external AREF pin
and that's why AREF pin needs a cap to AGND to improve the noise immunity.
Note that AREF pin is NOT tied to AVCC pin in 9XR board - I just checked with a voltmeter.
Desirable connections would be: GND->10uH->AGNDpin, VCC->10uH->AVCCpin->100nF->AGND and AREFpin->100nF->AGND.

[andrewju]

Thanks a lot! I think this time I got it right: v02 here.
I just don't think this board will fit the 9XR as it is deigned with the 9x case in mind...

P.S. This is not yet tested, so some things may be totally wrong. I'm going to recheck it in the next few days...

P.P.S. João, I did this as an enhancement to one of the boards described in the Wiki. There's no doubt that MegaSound is a great board! But this one is meant to take into account recent progress in the 9x development and introduce some advantages & new functionality (like telemetry, haptic feedback and analogue lines for future expansions).

[MikeB]

If anyone hasn't seen this, here is Gruvin's circuit for the 9X:
viewtopic.php?f=95&t=199&p=52925&hilit= ... ual#p52925

Mike.

[flybabo]

Nice design. It would be better if you use a separate 5V regulator for the haptic motor.
No, it can't be used for 9XR as it has a totally different power board
IMHO, Martin's design is the best suit for 9XR as he designed it for his 9XR.
viewtopic.php?f=5&t=948&start=3300#p48603
viewtopic.php?f=5&t=948&start=3300#p48718
viewtopic.php?f=5&t=948&start=3630#p91122
It's a well-thought-out simple design and easy to assemble since it uses a DIP 328p and 1208 SMD components.
It has a 7 pin header that can be shared by a USBASP programmer and a MicroSD card as they share 5 common signals.

You may also consider following things to simplify your design:

• If you're willing to use a cheap 5V MicroSD board found on eBay (http://www.ebay.com/itm/TF-ard-Reader-M ... 1509&rt=nc) rather than onboard MicroSD card connector, you can operate the sound card at 5V. This will eliminate 3.3V LDO with connected caps and allow you to increase the clock frequency up to 20MHz (=1.67x processing power) when you need it.

• If you're willing to program your sound card using a USBASP programmer, you can eliminate quite a few components associated with the serial interface - you don't even need a single Schottky diode. You just connect serial RX/TX pins to pin 27/28 of main board CPU and no need to install Optiboot loader. We'll have yet another firmware upgrading option using a MicroSD card - stay tuned

Just my $0.02.

[jhsa]

Yeah it would be nice to send the firmware file to the card over serial and then update the module. But is it really needed? I mean how often will we update the voice module? And it is possible to do it over serial, so... I am just installing an Atmega2561 in one of my radios and will power it using the regulator from the ArduVoice. It has a low dropout 1.5A 5V regulator, the L4940 V5.
It also uses a 5V micro SD module from ebay with a connector in it so I can update the bootloader if needed..

Joäo

[andrewju]

flybabo, I think another advantage is that powering the sound board from a 5V source will allow for greater precision of analogue inputs (if we will ever add any).

I did not plan to use that microSD board from eBay, but since it offers more flexibility - well, I need to think about it...

[flybabo]

Yeah it would be nice to send the firmware file to the card over serial and then update the module. But is it really needed? I mean how often will we update the voice module? And it is possible to do it over serial, so... I am just installing an Atmega2561 in one of my radios and will power it using the regulator from the ArduVoice. It has a low dropout 1.5A 5V regulator, the L4940 V5.
It also uses a 5V micro SD module from ebay with a connector in it so I can update the bootloader if needed..

Joäo

No, I don't need to send the firmware file to the card over serial.
All I need is to remove the SD card, put it on my laptop, copy the firmware file to the card and plug it in - that's it.
The SD bootloader (not Optiboot) will find the new firmware file from the card and program the sound card.
That's why I made the SD card accessible without opening the case.
We may need to update the firmware more frequently as we're adding more features.

[jhsa]

Ok, then you will need a different version of the firmware for your board I guess?
You will also have to flash a combined version of the firmware (Bootloader + amod) everytime there is a new version, correct?
I for example want to take advantage of the serial com. And I'm planning to also make my SD Card accessible, just in case I want to replace the voice pack completely. It is faster that way.
I will install a serial adapter inside the radio, so I will just have to connect a little usb cable, and I'm good to go.
Hmmm, That gave me another idea I can use a switch to connect MISO and MOSI (rx and tx) from the 9x and from the voice module in turn to the serial adapter.. Then I can just flick it to one side when I want to program the 9x over serial, and to the other when I want to communicate with the voice module, or flash it..
Once the 9x can also be programmed via a serial adapter since it has the bootloader, no need to use the usbasp anymore..

João

[flybabo]

No, the same firmware with a different bootloader.
After flashing the SD bootloader using a USBASP, all I need is to copy the same new firmware to SD card and plug it in whenever I get the new firmware.
Also, once we establish a reliable serial link between the mainboard and the sound card, we may be able to flash the mainboard (er9x) firmware same manner (from the same SD card) by implementing yet another bootloader for the mainboard and supporting code at the sound card.

At this moment, permanently installing a serial adapter appears to be not a good idea as Mike had a problem
sharing the serial link with a main board, a serial sound card and a serial adapter/programmer in certain situation.
viewtopic.php?f=5&t=2&start=2310#p94587
I'm sure that he will find a good solution but I guess it's tricky to implement without affecting the serial link usage.

[jhsa]

At this moment, permanently installing a serial adapter appears to be not a good idea as Mike had a problem
sharing the serial link with a main board, a serial sound card and a serial adapter/programmer in certain situation.

I've been running mine with a serial adapter always connected and it is working.. I can backup and restore models, and communicate with the PC without removing the serial adapter. I just needed a couple of diodes. It depends on which serial adapter you are using though. The picture below show my tests with different adapters. I'm using the cheap FTDI from ebay on this radio.. Maybe there is a more intelligent way of doing it, but the way I did it with my limited knowledge solved the problem and I have a fully working ArduVoice board, with serial in my radio now And with the adapter always connected

João

[flybabo]

When the sound card communicates with the main board back and forth, connected serial adapter must be in a mute state.
If I understand correctly, when Mike experimented various things, it sometimes confused the serial adapter and it caused a problem communicating between the sound card and the main board.
He implemented a workaround and it works for the current set up but this may limit the future enhancement.
Maybe I'm worrying too much too soon - you can always disconnect it if we have a problem in the future

[jhsa]

I don't understand why I would want to disconnect it. It will be inside the radio with only the USB plug showing. It's working very well. The only problem I have is that the audio is picking up some noise from the RF module.

João

[MikeB]

I don't have any problems. I'm using the transistor inverters and connecting to my PC using a USB to serial (RS232) adapter.
I only connect this, via a 3-pin connector in the battery bay, when I need it.

Mike.

[jhsa]

The problem with having the FTDI connected was that when not powered by the computer it would set the serial lines low. The diodes somehow overcome that situation..

João

[flybabo]

I don't have any problems. I'm using the transistor inverters and connecting to my PC using a USB to serial (RS232) adapter.
I only connect this, via a 3-pin connector in the battery bay, when I need it.

Mike.

What's the meaning of "...Not using the trim switch wasn't working at one point because the firmware was sending out the busy status and switch information all the time. This confused AvrDude. ..." in your posting?
I interpreted it as "Keep sending out something from sound card confuses AvrDude."

[MikeB]

If you power the Megasound on with a trim switch connected to it and holding the trim switch active causes the application to drop back to the bootloader.
If you power on normally, the application should recognise an attempt to synchronise by Avrdude and also drop back into the bootloader.
The problem was the application was sending switch and busy status very frequently and Avrdude saw this as an invalid response to its attempt to syncronise so Avrdude gave up.
Currently, the application only sends switch and busy status when they change, so Avrdude should work OK.

Mike.

[jhsa]

Mike, I guess, if we power the radio in bootloader mode the voice module will also start in bootloader mode, right? It is not necessary to hold the vertical trim at power up anymore, correct? I think it worked that way when I've tested it.. It will test when my radio is in working order again.. Too many mods in one go.. Got the ELE switch working as a 3 position switch using PC0 (pin 35 of the atmega..)
Guys, DO NOT power the radio from the voice module regulator. It will give you problems when flashing the radio as the voice module is also powered. Well, someone had to test it, right??
I also found out that the Atmega2561 is a little bit temperamental when flashing. Not mentioning that it is quite sensitive to static as well.. Don't even ask..

João

[MikeB]

No, powering on the radio in bootloader mode won't put the Megasound into its bootloader mode. However, the Megasound application should recognise Avrdude attempting to talk to it and drop into the bootlaoder.

Mike.

[jhsa]

Ahhh, then that is what happens, good..

Thanks

João

[flybabo]

Thanks for the explanation.
What I interpret is: if the sound card send out a bulk of serial data in uncontrolled manner, it may confuse connected Avrdude.
Ok, I've got what I wanted to know - let's worry about it later

[andrewju]

Guys, DO NOT power the radio from the voice module regulator. It will give you problems when flashing the radio as the voice module is also powered.

Can you elaborate on this? Is it something specific to serial communication between the voice module and the 9x?

I'm asking because I think I'm the one who first powered up the 9x mainboard from the voice module's VR. Back then the voice module was connected via LCD lines. I had a radio working this way for more than half a year - regularly updating via avrdude and USBasp. I saw no issues of any kind, it worked just great.

I also found out that the Atmega2561 is a little bit temperamental when flashing. Not mentioning that it is quite sensitive to static as well.. Don't even ask..

I didn't see any issues - neither with flashing, nor with static... And I installed quite some 2561's by now...

Something specific I should watch out for?

[jhsa]

Guys, DO NOT power the radio from the voice module regulator. It will give you problems when flashing the radio as the voice module is also powered.

Can you elaborate on this? Is it something specific to serial communication between the voice module and the 9x?

I'm asking because I think I'm the one who first powered up the 9x mainboard from the voice module's VR. Back then the voice module was connected via LCD lines. I had a radio working this way for more than half a year - regularly updating via avrdude and USBasp. I saw no issues of any kind, it worked just great.

As I said before, I have just replaced the m128 with a m2561.. I then decided to power the radio from the voice module's regulator. It has a L4940 V5, which is a 1.5A low dropout regulator. When flashing with my mySmartUSB Light programmer, it gave error.. But the chip don't like this programmer anyway, don't know why. This one powers the board only when flashing.
The UsbAsp powers the board all the time, and the radio with the voice module ON (Because it is connected to the 5V rail) was rebooting every time it left the splash screen. I decided to proceed with flashing anyway, and I nearly bricked the chip.The radio wouldn't turn on and every attempt to flash it failed.. Wrong signature (The m2561 seems to like this one). I had to flash it again using the -B100 option. That revived it again. Funny that it would read the eeprom Ok but it wouldn't flash.. I still didn't flash it since then as I just installed a new regulator on the radio. Will test later in the evening..
I do think it is important that the Voice Module stays OFF when flashing the radio, or maybe, have the radio powered ON and the voltage turned OFF in the programmer.. I think I tried that after it failed but it didn't work.. Maybe because it was already dead.. I really don't feel like testing the failure possibilities here as I'm not really in the mood to replace the chip again on this radio, and don't know if the mainboard would take another chip change, even using that amazing "Chip Quik" stuff.
Another possibility, is to flash the radio using serial with an FTDI adapter. That can be done as the radio has a bootloader. Maybe I should go back doing that. It takes a bit longer but I feel it is safer. I didn't try it yet with the m2561 though.

I also found out that the Atmega2561 is a little bit temperamental when flashing. Not mentioning that it is quite sensitive to static as well.. Don't even ask..

I didn't see any issues - neither with flashing, nor with static... And I installed quite some 2561's by now...

Something specific I should watch out for?

I had to replace the chip twice. The first one had a bad pin, the one that connects to the "Exit" key.. Also it would always give a wrong signature. It had some kind of identity disorder I managed to flash it using AvrStudio, and also change the fuses, but the signature problem never went away. My guess is that it was zapped with static. Maybe by me, or by the fact it came on a piece of cardboard and held to it with tesa tape..

[willhac]

I also had little problems when I replaced the 2 M64A by M2561 on my TXs :
viewtopic.php?f=95&t=3819&start=180
Now I use myAVR ProgTool for the flash, and eepe for the EEPROM, no problem doing like that.
But the other thing (I can't explain it) I had to do was to replace capacitor on the reset line (pin 20). It would drop the voltage on that pin.
Perhaps you don't have the same problem but it was the 2561 with mySmartUSB Light...

[jhsa]

Yes, I had to remove the 47uF capacitor on the reset line for my mySmartUSB Light programmer to work.. Now I'Ve soldered a 100nF cap in place.. I wonder if even the 100nF cap is causing problems.. I think I will remove it.. Will it be ok to run the radio without a cap there?

João

EDIT: Did you replace the capacitor or did you remove it??

[willhac]

I could flash without the cap, but I preferred to replace it by a capacitor of same value (higher voltage).

[andrewju]

I think I saw some reports (including this forum) stating that removing the cap on the Reset line helped to reflash the radio. Some people also said that the missing cap won't do anything bad to the radio - so the conclusion was that it is not needed at all.

For me, the USBasp (with a firmware posted on this forum) works just fine either with the stock cap and without it. So on my radio I never touch that cap at all, and if someone asks - I do not recommend to mess with it at all. I think there was a discussion about it in the USBasp firmware thread...

[jhsa]

Yes, but not everybody uses usbasp.. Also I had situations where the usbasp didn't work and the other did..
I'm glad I have both..
also sometimes avrdude can't flash the chips and AVRstudio4 can. And usbasp is not supported.. Avrstudio4 is by far the best programming tool I have used so far..

João

[andrewju]

As I said before, I have just replaced the m128 with a m2561.. I then decided to power the radio from the voice module's regulator. It has a L4940 V5, which is a 1.5A low dropout regulator. When flashing with my mySmartUSB Light programmer, it gave error.. But the chip don't like this programmer anyway, don't know why. This one powers the board only when flashing.
The UsbAsp powers the board all the time, and the radio with the voice module ON (Because it is connected to the 5V rail) was rebooting every time it left the splash screen.

I wonder what caused such a behavior. To me this is very important, as I plan to have the audio module powered ON at any time when the 9x mainboard is powered on. So if this causes an issue when flashing - I would definitely want to get it solved...

I had to replace the chip twice.

Funny... I had a similar issue with a 'mega328p on my first audio module. I also had to replace the chip twice - one of them programmed Ok but refused to start the code, and the second one had some other issue... But all the '2561s that I had - they worked without any issue and flashed by the USBasp at the first try.
Maybe you were "lucky" to get a pair of bad chips...

[jhsa]

Only one bad chip so far.. the second is working.. Will see, maybe I just remove the cap on the reset line.This is my test radio anyway, I'm testing other stuff on it as well..

João

[andrewju]

I think I have an idea!

The UsbAsp powers the board all the time, and the radio with the voice module ON (Because it is connected to the 5V rail) was rebooting every time it left the splash screen.

Is this about the time when the radio says "Welcome to er9x... " ?

The radio may have rebooted because it didn't get enough power. Normally, USB provides "up to 500mA" and in some cases some ports provide significantly less than that. Did you check the current consumption by your audio module? I think when it starts to play a file the power consumption increases beyond what your USB port could deliver - and then the voltage drops and the radio reboots.

P.S. I measured current consumption with my previous module and posted my results here. There is plenty of room to the 500mA limit. But since you have a different module - maybe some parts consume more than what I had in my case.