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2007-06-24 by larry barello
You have the ISP jumper cable installed correctly? Is the board set properly to drive the clock input of the chip? The 8515 is archaic and needs an external clock (IIRC). Is the ISP clock frequency less than 1/4 the CPU clock frequency? -----Original Message----- From: AVR-Chat@y
2007-06-24 by Thomas Keller
OK, perhaps I didn't explain my problem sufficiently. I can neither read data from the on board 8515, nor write data to it (in either program mode or control mode. I cannot read the fuses or lock bits, for example, nor can I program or otherwise write to the device on the STK-500
2007-06-24 by xolang1
ever tried max3000 from maxim? its a biderectional logic level translator,. Alexandre Guimarães wrote: Hi, I have to interface a 5 volts 160x160 LCD display to a 3.3 volts system and after reading the LCD specs I am quite sure that I will not violate the minimum voltage levels of
2007-06-24 by Roy E. Burrage
It's never a good idea to power an external circuit from your computer's supply. If there's a problem externally there's a chance you might let all of the smoke out of the computer supply...and once we let the smoke out, they quit working. At that point we have an external circui
2007-06-24 by Alexandre Guimarães
Hi, I have to interface a 5 volts 160x160 LCD display to a 3.3 volts system and after reading the LCD specs I am quite sure that I will not violate the minimum voltage levels of the inputs but I may have to use partially the LCD memory for other functions so I may have to use it
2007-06-24 by Cat C
I wrote the previous as soon as I could, in case speed was of the essence... to save your board. Then I gave it some thought, and... sure a diode is shorted, but I think it should still work. Sorry about that :-) Cat ----Original Message Follows---- From: "Cat" Reply-To: AVR-Chat
2007-06-24 by larry barello
Many AVR chips come factory programmed with internal 1mhz rc oscillator enabled. Those require an ISP frequency of 250khz or less to program. You find the ISP frequency on the "board" tab of the STK500 dialog. Once you get the ISP frequency correct, you can reprogram various fuse
2007-06-24 by Cat
I may be wrong, but DISCONNECT THAT IMMEDIATELY! USE A WALLWART! Ground of PC should not go to the power connector of the STK500, because there's a bridge rectifier there... You might have blown it. If I'm wrong, sorry about the panic :-) Cat ----- Original Message ----- From: "T
2007-06-24 by Thomas Keller
OK. I am new to development kits/systems. I have my STK-500 set up with power (beibng stolen from a disk drive power connector in my PC) and the serial connection. When I try to program in the switches and LED sample program, it fails, and the tip suggests checking clock frequenc
2007-06-23 by John Samperi
At 04:43 AM 24/06/2007, you wrote: >Code ......dosen't work in ice. Maybe it's against union rules...too cold!! :-) For your reading pleasure: http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=50435 Don't know if the above bug will mess up the ICE50?? but it messe
2007-06-23 by Dave VanHorn
Continuing saga.. Debugging comm software talking to USART1. Code looks good, but plain dosen't work in ice. Take off ice, put on real M128 chip, code is fine. ICE is NOT in M103 mode, can't see any reason for what's happening. Bytes written to UDR1 never come out. Bytes that com
2007-06-22 by David VanHorn
> If you mean the cycle counter in AVR Studio 4.13, I found it by > switching to debug mode. Once in debug mode, the cycle counter is > found in its own window titled "Processor". The "Processor" window > can be toggled on and off by navigating the menus: > View->Toolbars->Proces
2007-06-22 by Rick
--- In AVR-Chat@yahoogroups.com, "Dave VanHorn" wrote: > > > In the new simulator, does anyone know where the timer is that counts > machine cycles (xtal)? Either they took it out, or they moved it > somewhere that I haven't found yet. It used to be part of the I/O > window, unde
2007-06-22 by Dave VanHorn
In the new simulator, does anyone know where the timer is that counts machine cycles (xtal)? Either they took it out, or they moved it somewhere that I haven't found yet. It used to be part of the I/O window, under what is now "CPU and system control". I hope they haven't "improv
2007-06-21 by Dave VanHorn
--- In AVR-Chat@yahoogroups.com, "Dave VanHorn" wrote: > > > Resolved, sort of.. > > It's a bug in the sim. Lucky me. Confirmed this morning by Atmel.
2007-06-20 by John Samperi
At 12:25 AM 21/06/2007, you wrote: >the 49 Ohm pull up resistor at the other end of the line. The first thing is to try and remove the possibility of shorts to VCC. Is the resistor tied up to 5V at the other side? That would be a 100mA sink you are trying to get from a pin!! Even
2007-06-20 by kholt@sonic.net
You might consider leaving it as is. Most of the AVRs can take a short to VCC without killing the device. Is the short likely to happen during development, or in use? Short or long time? With or without a buffer, a short will cause loss of functionality during the short; you may
2007-06-20 by David VanHorn
On 6/20/07, mago Umandam wrote: > A series resistor was my first solution but it didnt work because of the the 49 Ohm pull up resistor at the other end of the line. when the uC pin set the line low, the output voltage will become a voltage divider and is quite high unless i will
2007-06-20 by mago Umandam
A series resistor was my first solution but it didnt work because of the the 49 Ohm pull up resistor at the other end of the line. when the uC pin set the line low, the output voltage will become a voltage divider and is quite high unless i will use a very low series resistance (
2007-06-20 by Ralph Hilton
On Wed, 20 Jun 2007 09:43:47 -0000 you wrote: What does the output pin normally drive? How does it get shorted to VCC? > >Hello guys.. I have an application where in the output pin has a >greater posibility being shorted to VCC. Now when this pin is set low, >it causes high curre
2007-06-20 by David VanHorn
There's a lot of unsaid things here, even a series resistor might work, depending on what you're doing with the pin.
2007-06-20 by Ned Konz
magzky02 wrote: > Hello guys.. I have an application where in the output pin has a > greater posibility being shorted to VCC. Now when this pin is set low, > it causes high current. To avoid this, i am thinking of placing a > buffer after the output pin (i dunno if this is the be
2007-06-20 by magzky02
Hello guys.. I have an application where in the output pin has a greater posibility being shorted to VCC. Now when this pin is set low, it causes high current. To avoid this, i am thinking of placing a buffer after the output pin (i dunno if this is the best idea, i appreciate fe
2007-06-20 by Robert Adsett
At 05:25 PM 6/19/2007 +0000, Dave VanHorn wrote: > Your only delay now is how long it takes to charge that > > cap through the resistor network - but since this is a slowly changing > > signal (one hopes!) that shouldn't matter. > > >The source resistance still matters, because t
2007-06-20 by David VanHorn
On 6/19/07, Darren Worley wrote: > Finally, someone read the actual task, and come back to reality. > It's great to see discussion on such topics, but sadly, us techies can get > so tied up in the design intricacies at times, we really need to keep > focused on the end goal and s
2007-06-20 by Darren Worley
Finally, someone read the actual task, and come back to reality. It's great to see discussion on such topics, but sadly, us techies can get so tied up in the design intricacies at times, we really need to keep focused on the end goal and stay in perspective. Albeit, its fun at ti
2007-06-20 by Ralph Hilton
On Mon, 18 Jun 2007 23:00:54 -0600 you wrote: We are talking about a battery voltage indicator needing 3 bits resolution max. Lets get a bit more real here. Keep it simple. The original requirement was: "I'm using the ATmega48V in a project and I need to monitor the battery level
2007-06-20 by David VanHorn
> Of course, "everyone" knows this, right? Sure! :)
2007-06-19 by Jim Wagner
On Tue, 19 Jun 2007 18:39:45 -0400 "David VanHorn" wrote: > > And Op-Amps have their own input "leakage". > > > > Indeed, but the chip processes that do good analog are > different from > the ones that do good microcontrollers. No argument there. Point, however: suppose that an o
2007-06-19 by David VanHorn
> And Op-Amps have their own input "leakage". > Indeed, but the chip processes that do good analog are different from the ones that do good microcontrollers.
2007-06-19 by John Samperi
At 03:22 AM 20/06/2007, you wrote: >It's a bug in the sim. Well you should report it to Atmel ...for what is worth. They will simply say that the simulator is not perfect etc :-( It seems that many things got really messed up with the M128 in this version. Look at the USART1 addr
2007-06-19 by Jim Wagner
On Tue, 19 Jun 2007 19:35:43 -0000 "Dave VanHorn" wrote: > > > I'm still curious enough to experiment with this idea > compared to my > > typical OpAmp solution. > > It may "work" on one unit, but if you can't handle the > leakage allowed > in the spec without significant error,
2007-06-19 by kernels_nz
Firstly, the ADC uses 3 ADC clock cycles to perform it's sample and hold. You can calculate the sample and hold time by multiplying your ADC clock period by 3. Secondly, the ADC must be fed from a low impedance source - have a look at the input with your scope when your feeding i
2007-06-19 by dlc@frii.com
> Your only delay now is how long it takes to charge that >> cap through the resistor network - but since this is a slowly changing >> signal (one hopes!) that shouldn't matter. > > > The source resistance still matters, because the AVR inputs have > leakage currents into or out
2007-06-19 by Dave VanHorn
> I'm still curious enough to experiment with this idea compared to my > typical OpAmp solution. It may "work" on one unit, but if you can't handle the leakage allowed in the spec without significant error, then you're in trouble. Remember, you have to add this error to all the o
2007-06-19 by dlc@frii.com
> 1) The concept here is that the 0.1uF cap is way larger than the input cap > in the A/D and will present a low impedance source to the input. True, a very low impedance. > 2) What do you mean by "a certain RC charge rate?" AFAIK, the slope has > nothing to do with the A/D measu
2007-06-19 by Cat
The word "across" in your message I quoted means something to me. Big or Small doesn't make a difference (still LPF, better or worse). ----- Original Message ----- From: To: Sent: Tuesday, June 19, 2007 9:16 AM Subject: Re: [AVR-Chat] Using the ADC to measure the battery supply?
2007-06-19 by Dave VanHorn
Your only delay now is how long it takes to charge that > cap through the resistor network - but since this is a slowly changing > signal (one hopes!) that shouldn't matter. The source resistance still matters, because the AVR inputs have leakage currents into or out of the pins.
2007-06-19 by Dave VanHorn
Resolved, sort of.. It's a bug in the sim. Lucky me. If I turn off the WDT, then I never get reset. If I have the main loop doing nothing but WDR instructions, and the WDT is enabled, then I get reset. But on reset, the appropriate flag bit is NOT set, which would have indicated
2007-06-19 by dlc@frii.com
> I'm also curious, but a cap IS a low pass filter. Depends, series or shunt? Big cap or small? DLC > Cat > ----- Original Message ----- > From: "dlc" > To: > Sent: Monday, June 18, 2007 11:00 PM > Subject: Re: [AVR-Chat] Using the ADC to measure the battery supply? > > >> If the
2007-06-19 by subscriptions@aeolusdevelopment.com
Robert Wrote >That's a caution that the s/h cannot track a rapidly changing signal. It, >after all, forms a low pass filter as well. Also the cap will form a low >pass filter with the divider with quite a low frequency given the resistor >values. The signal simply will not change
2007-06-19 by subscriptions@aeolusdevelopment.com
dlc Wrote >If the cap is across it then the ADC might not get the correct voltage >either. The ADC relies upon charging a cap inside the module. That >relies upon a certain target RC charge rate, that charge rate also must >not exceed the current capacity of the pin. Say what!? Y
2007-06-19 by Dave VanHorn
My M128 app is ending up back at the reset vector in sim, after running for several seconds. The interesting thing is that I'm not getting any flag bits to say WHY I got reset, I just end up there... SP is cleared, everything looks like I just had a powerup reset again, but that
2007-06-19 by Phillip Vogel
1) The concept here is that the 0.1uF cap is way larger than the input cap in the A/D and will present a low impedance source to the input. 2) What do you mean by "a certain RC charge rate?" AFAIK, the slope has nothing to do with the A/D measurement, other than to say that you w
2007-06-19 by Cat
I'm also curious, but a cap IS a low pass filter. Cat ----- Original Message ----- From: "dlc" To: Sent: Monday, June 18, 2007 11:00 PM Subject: Re: [AVR-Chat] Using the ADC to measure the battery supply? > If the cap is across it then the ADC might not get the correct voltage >
2007-06-19 by dlc
If the cap is across it then the ADC might not get the correct voltage either. The ADC relies upon charging a cap inside the module. That relies upon a certain target RC charge rate, that charge rate also must not exceed the current capacity of the pin. You are playing a finicky
2007-06-19 by Ralph Hilton
On Mon, 18 Jun 2007 15:44:07 -0600 (MDT) you wrote: >Most microcontroller's ADC will not like a 10M load, the charge time will >be very high and not very accurate. I have used a low power OpAmp to run >very high Z dividers into and the output of the OpAmp is nicely low Z for >tha
2007-06-18 by John Samperi
At 01:34 AM 19/06/2007, you wrote: >A more efficient alternative is to use a macro >An example GNU Assembler macro for input is shown below. Atmel's macros.inc (AVR001 app notes) contains a few useful macros for the AVR assembler. The zip file is only 1k. It has become one of my
2007-06-18 by David VanHorn
On 6/18/07, kernels_nz wrote: > This is excellent advice from Bob, using a fet to connect / disconnect > the power supply to the voltage divider also means you can use lower > value resistors for the divider, I have had some issues with resistors > > 1M OHM. This is documented, t
2007-06-18 by dlc@frii.com
Most microcontroller's ADC will not like a 10M load, the charge time will be very high and not very accurate. I have used a low power OpAmp to run very high Z dividers into and the output of the OpAmp is nicely low Z for that ADC to be happy with. Its a few more pins and passive