Hi all, I've got an MSP430F149 on a PCB and the ADC is not working. Using the same code on another board, I get data from it sucessfully, both on the external and internal channels. This is using custom software, but the same works with one of the TI ADC code samples (adc-04 from memory). However, on this board, all channels, internal and external, return 4095 (maximum value). I have tried it initially using the 2.5 internal reference, but then also using AVcc (3.3V) as a reference. When set to 2.5V, I do get 2.5V on the Vref pin, and from all accounts it looks like the ADC works (the interrupt goes off, etc...) I'm thinking I've blown up something on the hardware given that one board works and the other doesn't, however wondering whether there were any other things to try given, a. looks like it receives power given the internal reference works b. If I'd blown up a pin, I would have thought only that channel would die, and at least the internal Vcc measurement would still work Any thoughts before I go and replace it out of frustration? Regards, Rob
ADC problems
Started by ●September 10, 2003
Reply by ●September 11, 20032003-09-11
Hi. I have the same problem. I have used three programs that work!. but the ADC returns always 4095. it looks that channels configuration doesn`t work!. I think the basic problem is hardware, (because my program worked a day and I didn't modified anything!!).I haven't found yet where is the error. Do you know about any application note where explain any typical hardware configuration for the ADC12 converter? --- In msp430@msp4..., Robert Reid <robreid@c...> wrote: > Hi all, > > I've got an MSP430F149 on a PCB and the ADC is not working. Using the > same code on another board, I get data from it sucessfully, both on the > external and internal channels. This is using custom software, but the > same works with one of the TI ADC code samples (adc-04 from memory). > > However, on this board, all channels, internal and external, return 4095 > (maximum value). I have tried it initially using the 2.5 internal > reference, but then also using AVcc (3.3V) as a reference. When set to > 2.5V, I do get 2.5V on the Vref pin, and from all accounts it looks like > the ADC works (the interrupt goes off, etc...) > > I'm thinking I've blown up something on the hardware given that one > board works and the other doesn't, however wondering whether there were > any other things to try given, > a. looks like it receives power given the internal reference works > b. If I'd blown up a pin, I would have thought only that channel would > die, and at least the internal Vcc measurement would still work > > Any thoughts before I go and replace it out of frustration? > > Regards, > Rob
Reply by ●September 11, 20032003-09-11
francisjjp wrote: >Hi. I have the same problem. I have used three programs that work!. >but the ADC returns always 4095. it looks that channels >configuration doesn`t work!. I think the basic problem is hardware, >(because my program worked a day and I didn't modified anything!!).I >haven't found yet where is the error. Do you know about any >application note where explain any typical hardware configuration >for the ADC12 converter? > > There's a block diagram in the SLAS272 (MSP430x14x datasheet), guessing I've somehow blown up the multiplexor or sample and hold part or similar. When getting the ADC going for the first time, I found the c-code examples from the TI website very helpful, but alas the sample program that worked on another board does not work here. I guess I'll replace the part tomorrow and hope it fixes it (just a pain getting QFP64s off the PCB). I went through the errata pages (once they eventually worked - they say to be patient but I can't believe they are THAT slow) and couldn't find anything similar. Regards, Rob > > > >--- In msp430@msp4..., Robert Reid <robreid@c...> wrote: > > >>Hi all, >> >>I've got an MSP430F149 on a PCB and the ADC is not working. Using >> >> >the > > >>same code on another board, I get data from it sucessfully, both >> >> >on the > > >>external and internal channels. This is using custom software, >> >> >but the > > >>same works with one of the TI ADC code samples (adc-04 from >> >> >memory). > > >>However, on this board, all channels, internal and external, >> >> >return 4095 > > >>(maximum value). I have tried it initially using the 2.5 internal >>reference, but then also using AVcc (3.3V) as a reference. When >> >> >set to > > >>2.5V, I do get 2.5V on the Vref pin, and from all accounts it >> >> >looks like > > >>the ADC works (the interrupt goes off, etc...) >> >>I'm thinking I've blown up something on the hardware given that >> >> >one > > >>board works and the other doesn't, however wondering whether there >> >> >were > > >>any other things to try given, >>a. looks like it receives power given the internal reference works >>b. If I'd blown up a pin, I would have thought only that channel >> >> >would > > >>die, and at least the internal Vcc measurement would still work >> >>Any thoughts before I go and replace it out of frustration? >> >>Regards, >>Rob >> >>
