This data sheet contains limit values extracted from processors. AVR32 extends the AVR family into the world of and bit applications. Features. • High Performance, Low Power bit AVR® Microcontroller. – Compact Single-cycle RISC Instruction Set Including DSP Instruction. AVR32 extends the AVR family into the world of and bit Characteristics chapter at the end of this datasheet for details on the max-.
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In this exercise, let’s build a microphone preamp on the protoboard, acquire the audio signals on the AVR32 using the ADC, process the auditory signal to measure the RMS power sound volumeand then use the average sound volume over the past few hundred ms of time to set the position of a servo motor.
To achieve this, we need to interface to and control a servo motor and build a microphone preamplifier. Let’s use the protoboard for both of these. If you finally have to give up for lack of time or success, a solution will be revealed in two weeks. Follow the following general steps to complete this exercise:. Let’s copy the usb-rgb-ldr project to a new one called mic-servofollowing the instructions given at http: Let’s modify this project so that we produce a suitable servo output signal in response to the sampled sounds from the ADC.
Ahh, but we can’t, can we? This one is available, so let’s use it.
These choices determine the clocks available to individual PWM channels:. You also need to initialize the servo PWM channel to use one of these available clock sources, to end up with a period of about Hz. An existing LED channel looks like this:. The prescaler is what you need to change; it is set to 2 above and you need to increase it to reduce the servo pulse frequency.
The 20 bit cdty field sets the duty cycle and the 20 bit cprd field sets the period, in units of the PWM channel clock period, which is set by the clock you choose with the cpre field.
To see what this all means, look at the following block diagram, from the datasheet. Period is a 20 bit value that determines the pulse period. DutyCyclewhich must be smaller than Perioddetermines the duty cycle. Update is a register that you load and on the next cycle the duty cycle contents are replaced. This way, no funny partial cycles will occur. Counter is a read-only register that lets you examine the current counter value.
You will end up with about 4V to power the servo which is on the low side but it should still work. To test the servo code, modify firmware so that the LED PWM value sent from the host now sets the servo position as well.
The RGB values range from You can also use one of the colors to set the servo position. We’ve already built the microphone preamp circuit on the protoboard, using a JEFT microphone datasheetresistors, capacitors, and an LMN quad opamp. Now let’s write a main loop that samples the microphone input, computes the average mean square sound level, low pass filters it, and sets the adtasheet according to this sound volume.
Ideally you would datwsheet at a regular rate set by a timer interrupt, but here we do everything in a polled way because it is much simpler to implement. We could use software delays to slow things down enough.
Atmel AVR32 vs Prop
Remember dwtasheet you only have fixed point hardware. The ADC samples are 10 bits expressed as the 10 lsbs of a U16 value. You can add up a lot of 10 bit values in a 32 bit value. This call toggles PA Referring again to the AVR32 datasheet in section 4.
Looking at the copper or bronze schematic, we can find this pin on the board. Here we’ll use the copper board, where the corresponding PA04 pin is on the bottom row 5th from the left end.
We won’t worry about putting the ADC sampling in a timer interrupt routine for now. You can then use the USB communication part of the function to send back your computed sound volume, to check whether your computations make sense. You should probably do your signal processing using signed and unsigned 32 bit ints int and unsigned intor S32 and U To activate the DSP functions, you need to add this module to your project framework, using the menu satasheet Framework.
You could also try to run the ADC in a timer interrupt to sample at a regular rate. See this example to start. To better work in python, you may want to install in Eclipse the plugin to handle python projects. Then you will be able to create a python project in Eclipse and edit and run the python code from eclipse.
Atmel AVR32 vs Prop — Parallax Forums
On the datashee side, the python method usbio sends the RGB bytes and takes the byte buffer values sent from the device to reconstruct the 16 bit ADC sample as shown below:. You can modify this code to pass to the adc method shown below the reconstructed the 32 bit rather than 16 bit sound volume value you compute on the device side and print it out in the adc method:.
The print methods may be unfamiliar to you. You can add a field after this on the next line to print your sound volume value. Remember that python syntax uses indentation to mark code blocks! You demo should end up responding to transient sound volume increases by turning the servo. Congratulations if you get all this to work! It seems as though there is a large amount to learn to use a rather simple processor like the AVR But if you work with a device like this for a while you will get familiar with it and it will become quite easy to write new functionality.
If you finally have to give up for lack of time or success, see how to make the mic-servo application work. Table of Contents Lab 3.
Sampling audio and signal processing. Note these instructions are somewhat outdated by switch to Arduino Nano in Follow the following general steps to complete this exercise: Build the microphone preamplifier on the solderless breadboard to amplifier the microphone signal. One person can do this while the others in a group can work on the next parts. Sketch an outline flow diagram of your application, including the AD conversion, satasheet servo control, the signal processing.
Datasneet the PWM code to control the servo.
dig:lab_3 [Tobi Delbruck wiki]
Demonstrate your working system to Tobi and send your project by zip or. The header pins we plug into the solderless breadboard are here: Decide on a new PWM output pin for your servo output pulses. These are pins 12, 26 and 27 on the AT32UC3. Then us will be the center servo position and and the extremes. You don’t need to be exact about this since the PWM has a limited clock source division and prescaler choice.
The pseudo code for the signal processing should go as follows: Get an ADC sample. Update the fading average sample value. We need to subtract this from the sample to get the deviation from the mean. You may notice certain calls such as the bit banger: Some hints for signal processing using fixed point: To multiply by a fraction, multiply by the numerator and then divide by the denominator.
And don’t forget to add the include statement at the start of your main. Let’s use the host side to debug the device. On the host side, the python method usbio sends the RGB bytes and takes the byte buffer values sent from the device to reconstruct the 16 bit ADC sample as shown below: See uc for AVR32 tool setup and example firmware. Page Tools Backlinks Back to top. Except where otherwise noted, content on this wiki is licensed under the following license: