ADC block for F280x
Altair EmployeeSubmitted by KM7 on Thu, 10/15/2009 - 21:48
Hello! I´m trying to use the analog input of a DSP. I use the block showed in the pannel Vissim/DSP----->F280x blocks----->analog/digital input. I configure that block like an analog input in the chanel 0 and target board 0. I use a TMS320F28335, and the datasheet show that ports 5 and 9 are the analog inputs (from ADCINA0 to ADCINA7 and ADCINB0 to ADCINB7). I use the pin 1 of the port 5 and the pin 2 of the port 9, but the DSP doesn´t recognize my input. So, where is the problem? Do I use an incorrect block? Or may I configure other parameters? Thank you in advance.
Answers
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Submitted by Anders89 on Fri, 10/16/2009 - 00:24.
Hi KM7, There is an important note in the Spectrum Digital pdf: 'Connect ADCLO to AGND or ADCLO of target system for proper ADC operation.' This means that the GND pins put helpfully next to the ADCxx pins are useless unless you connect ADCLO to GND (jumper P9.18 to P9.19). You can also configure the sample time, channel sample order, and trigger source for each ADC bank with the VisSim/DSP > F280x > ADC Config... dialog. (This only affect the compiled .out file, not interactive operation). Note that the Piccolo version of this dialog allows trigger source selection on a per channel basis instead of per 8 channel bank.
Attached below you can find a simple diagram to read ADCINA0 and blink the LED on GPIO32. There are 2 diagrams:
- ADCin-28335.vsm (source diagram that can be run interactively)
- ADCin-28335-d.vsm (debug diagram that downloads and runs the .out file created by compiling the file above with Tools > Code gen... > Compile with Include VisSim Communication Interface checked.
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Submitted by KM7 on Tue, 10/20/2009 - 18:45.
Hello anders! Thanks for your answer. I short-circuited GND with ADCLO and the DSP works properly. But now I have a new doubt: how can I use an analogic output? If I design a project with an analogic input and an analogic output, then the compiler gives me an error. do you know where is the error? and, in wich pins should I have my analogic output? Thanks a lot.
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Submitted by Richd on Tue, 10/20/2009 - 19:02.
Hi KM, There is only analog output on the new Piccolo processors. The F2808 does not have one. Normally the PWMs are used for output control.
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Submitted by KM7 on Tue, 10/20/2009 - 21:58.
but I have the F28335, not the F2808. Has F28335 analogic outputs? I´ve seen de technical reference, but I don´t see anything. Thanks a lot.
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Submitted by Anders89 on Wed, 10/21/2009 - 10:32.
You can get a Piccolo (F28035) cheap though. Why do you want an analog output? Just use the PWM.
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Submitted by KM7 on Wed, 10/21/2009 - 22:33.
For the moment I don´t want the analog output for nothing special, it was only for a future purpose. Yes, by the moment I can work perfectly only with the PWM. Thanks.
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