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61  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 07, 2008, 11:01:00 am
i'm positive that the missing resistor didn't destroy your board. plus i don't see why it is needed at all. 470[ch937] - 10k[ch937] is quite a large range anyway. maybe it's a gameboy specific thing?

if you look at the Diecimila schematics, there are 1k[ch937]  resistors between each the TX/RX pins and the FTDI chip. so i guess another 1k wouldn't make much of a difference. 10k probably couldn't even work, because of the pulldown resistor on the RX in the new design. (i can't find it in the schematics, but i remember that there is one on the newer boards... anyone knows abou that?)

do you use a Diecimila or older arduino?

62  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 02:20:02 pm
the page you mentioned states that the keyboard would only function after pressing the sms button.
otherwise i'm not sure. if the keyboard sends data you should be able to see it in hyperterminal if you were able to use this with your arduino before. even with the wrong baud rate something should show up.

did you connect both pins (1 & 5) to Vcc on the keyboard like shown on that site?
GBA ----------- Chatboard
2 --------------- 4 (Chatboard serial in)
3 -------[R]----- 2 (Chatboard serial out)
6 --------------- 3 (GND)
1 --------------- 1 and 5 (Vcc)
1kohm is a suitable value for the resistor R, but you can really use anything between 470ohm - 10kohm.
Both pin 1 and 5 on the chatboard must be connected to pin 1 on the GBA link port.

63  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 11:46:41 am
we're fast. i probably should wait a little before writing responses on responses :-)
Cool, thanks!

I haven't connected ground to Arduino ground currently (I connected chatboard ground to the ground pin of the vreg). Could that cause the garbage?


yes. it is. devices need a <b>common</b> ground to interpret the ones and zeros of each other.
note that you will have to connect the keyboard to both "grounds", effectively connecting "all grounds" to one common. i wasn't sure if that was clear.

64  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 11:38:39 am
I am getting garbage all the time... I can't see very well if there is a change in the data when I press a key.

that's hard, i agree. in that case it wouldn't be bad to use a programmable environment rather than a plain serial port data viewer.
regarding my hard time with midi, i programmed the arduino to light up an led as response to certain serial byte.

whatever character encoding the keyboard uses, if you pick a rondom number from 0-255, chances are that there is a button for it, which you can try to find out.

still i'd avoid using the software serial until you've had at least some success.

65  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 11:27:04 am
I think this would be a test thing to start with. So, to be sure I understand this correctly, I can remove the Atmega chip from the socket on the Arduino, connect the rx and tx coming from the chatboard to pins 0 & 1 on Arduino and then connect the Arduino (through USB) to my PC?

yes. you'll have to connect ground to ground too though, even if you power the keyboard form an external source!

66  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 10:56:03 am
i forgot:

you dont know about the character encoding of the keyboard, do you? if the garbage you get is reproducable (always the same for a certain key) it's probably no garbage. and don't let the garbage (when no key is pressed) discourage you. when debuggig midi-input, i experienced the same with my (midi)keyboard and this gave me leepless nights. when i got the hardware right i learned, that the keyboard was just sending some status information continouusly, which could just be ignored.
67  Forum 2005-2010 (read only) / Troubleshooting / Re: Interfacing Arduino with Ericsson chatboard on: February 06, 2008, 10:48:12 am
hej jds,

not sure if it will help as this old news. but you can just take out the atmega on your arduino and use the RX TX pins then to communicate directly from the keyboard to you computer. i've never used "software serial" on the arduino, so can't comment on its reliabilty. but i think it could be helpful for debugging to rule out programming issues.

you could also easily try different baud rates. the keyboards serial specs you wrote seem quite promising, though sometimes these mobile phone things are more complicated as they seem. i'm thinking of some kind of sony ericsson hand shaking at a different baud rate first or a an amperage check so that it wouldn't work with neither less <b>nor</b> more than 200mA.

(you write 200mAh, this doesn't tell us about the peaks, still the arduino power regulator or USB should have no problems in providing the current for this thing)

i think a SE phone would be able to recognize the attached keyboard and model. so who knows, maybe they even built in something so that the keyboard can identify the attached phone!?

best, kuk

68  Forum 2005-2010 (read only) / Troubleshooting / Re: Proper Voltage Supply on: February 01, 2008, 02:22:31 pm
kuk: the reference is Vcc, but the issue is that when directly connected to the battery, the actual voltage will depend on the load, the amount of charge left in the battery, ambient temperature, etc.  In order for Vcc to be a useful reference, it must be stable.

this actually what i meant... somehow... i only thought of using trim pots though. where half a turn would read 512 out of 1024 no matter what Vcc actually is, right? you're right that absolute values won't work this way.
69  Forum 2005-2010 (read only) / Troubleshooting / Re: Proper Voltage Supply on: February 01, 2008, 12:14:36 pm
So what do you think about the jumpers on the Boarduino bypassing the regulator and running it on 3.7V ?

I think the analog inputs will be useless (without adding an external reference, anyway), as the reference voltage is off.

i thought the analog reference was vcc by default?
70  Forum 2005-2010 (read only) / Troubleshooting / Re: Proper Voltage Supply on: January 30, 2008, 09:03:52 pm
have a look into switching regulators. this site got me started:
it would be nice to hear something from the more experienced on this topic.
what about the MC33269D in the current Diecimila design? i understand that it's a low dropout regulator, but isn't it quite inefficient on 9v and more? i think this is definetly worth being discussed a little. it took me a year to realize that probably more than half of the batteries i killed, was due to using ordinary 7805s for everything (inspired by the original arduino design). the design wasn't bad, i just didn't know the loss in energy would grow with each servo/led/etc.

71  Forum 2005-2010 (read only) / Troubleshooting / Re: Simple LED setup causing lots of strange probl on: January 25, 2008, 05:31:26 am

verifying the brownout fuses might also be a good thing to do.

i want to second that. if it's not the bootloader overwriting your program, it totally sounds what i was experiencing while breadboarding with the atmega and unstable power-supply. the program (or even the bootlaoder itself) would get lost sooner or later on a couple of chips. until i found out that the script i used to burn the bootloader disabled brow-out detection. since enabling it for 2,7v everything works fine just on batteries, no caps, no regulator (i can't tell if it restarts very often, but it definetly stopped forgetting programs).


72  Forum 2005-2010 (read only) / Troubleshooting / Re: Did I Kill My Diecimila? on: January 12, 2008, 12:02:43 pm
i'm sorry for you. if all connections are fine and you did not mess up with the soldering, there's probably something wrong with the atmega. i don't know if this should happen or how it happens, but probably just the bootloader got lost or blocked. this happened like 3 times to me, while switching boards (a million times). since the parallel cable wouldn't work on a mac i bought a mkII with usb.

those 3 atmegas8 and 168 could easily be recovered by burning a bootloader again. if the parallel cable is an option for you, go for it. if you plan to do more with arduino you'll appreciate to be able to burn your own bootloaders on 3euro raw atmegas.

73  Forum 2005-2010 (read only) / Troubleshooting / Re: mini on 3.3v on: January 18, 2008, 06:10:40 am
The mini doesnt have a regulator.

Give it 3.3v and it should run just fine.

if you look at the schematics, it does have one:
but if i read it right, you can circumvent it by using the 5v in.

you might get little problems though if the atmega was configured for brownout detection. AFAIKT this is to shut it off automatically if the voltage drops below a certain point to save the flash memory.

if you have a mini it should be save to just try it.
[EDIT: daniel pointed out that the regulator might not like the reverse voltage of 3.3v. you should keep that in the back of your head. still i think, it shouldn't burn anything as the mini works fine on the 5v from the USB adaptor ]

74  Forum 2005-2010 (read only) / Troubleshooting / Re: transfererror on: January 03, 2008, 09:56:28 am
you should also double check that the atmega sits firmly in its socket. just sometimes this helped me.

75  Forum 2005-2010 (read only) / Troubleshooting / Re: burn sketch only once - 2nd time doesnt work on: September 29, 2007, 03:40:07 pm
i just managed to get the same behaviour with the first two atmega168s that i burned by accident. after uploading a program the bootloader wouldn't execute anymore. it turned out to be a fuse setting ("Boot Reset Vector Enabled") that i left untouched... the bootloader wasn't overwritten but merely not started as nkcelectronics just explained. i knew this thread would be helpful for me in some way . thank you

i have now successfully burned my first two bootloaders onto fresh atmegas .

maybe you can ask adafruit for a discount on a programmer rather than sending back the "faulty" chips to get them set right. circumventing the bootloader is a nice feature. if you have control over it i mean.
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