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Running the example

Connect an audio source to J14, a speaker / headphone to J4 and check Path #1.

Connect an audio source to J13, a speaker / headphone to J5 and check Path #2.

Principle of operation

The main idea is to create a Simulink environment that reads samples form 4 channels, process them and send them to 4 output channels. The example model is shown in Figure 14.

Simulink Environment for Multichannel Processing

The Simulink driver block is based on the driver described in the previous chapters. Both drivers read and write samples using a double-buffering mechanism, but they differ in the way they activate the processing algorithm.

The algorithm code, in the Simulink environment, runs as a separate free-running task. At the start of the function it checks the semaphore to see if data is ready to read from the buffer – if not then it stays in a wait state until the semaphore is posted by the callback routine (Please refer to section ). Once this has been posted, it reads the data elements from the addresses supplied by the appropriate pointers. Once the algorithm has then processed the data, it writes the data elements from the addresses supplied by the appropriate pointers. After process is concluded, it will wait for the next frame of samples. This process then repeats until halted.

The callback function, in the Simulink environment, needs to set the appropriate pointers each time an EDMA interrupt occur, and post a semaphore for the “Algorithm” task afterwards.

Driver structure

The driver consists of 4 files:

  1. ”aic24_defs.h” – This file contains the definitions of the various registers of the TLV320AIC24.
  2. ”aic24.h” – Needed for the DSP configuration.
  3. ”aic24.c” – Contains the various initialization routines.
  4. “aic24link.c”

The first three files are the same files used for the CCS driver. The ai24link.c file is similar to the user defined file (test.c for example) described in ,

This file contains the following functions and definitions:

Buffers definitions:

Int16 r_data1[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for readInt16 w_data1[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for readInt16 r_data2[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for writeInt16 w_data2[DATANUM*NUM_CODECS*BUFS_PER_CHANNEL]; // data buffer for write

Pointers to each channel buffers (read and write).

Those pointers are used by the Algorithm block in the Simulink model. Int16 *InSig1; Int16 *InSig2;Int16 *InSig3; Int16 *InSig4;Int16 *OutSig1; Int16 *OutSig2;Int16 *OutSig3; Int16 *OutSig4;

An aic24 handle and a semaphore handle

As explained the semaphore will be used to wait for the data to arrive. AIC24_Handle hAIC24; SEM_Obj AIC24_ready_sem;

It calls the AIC24_Init function and also initializes the semaphore. void AIC24LINK_init() {// setting up the AIC24 handle AIC24_InitDefaults(⩓hAIC24, NUM_CODECS, DATANUM, r_data1, r_data2, w_data1, w_data2, AIC24LINK_process);SEM_new(⩓AIC24_ready_sem,0); }

The callback function.

The callback function AIC24LINK_process simply sets the channel buffer pointers (the pointers the model uses) to the correct places and posts on the semaphore. void AIC24LINK_process(Int16 *r_data, Int16 *w_data) {InSig1 = r_data; InSig2 = r_data + DATANUM;InSig3 = r_data + DATANUM*2; InSig4 = r_data + DATANUM*3;OutSig1 = w_data; OutSig2 = w_data + DATANUM;OutSig3 = w_data + DATANUM*2; OutSig4 = w_data + DATANUM*3;SEM_post(⩓AIC24_ready_sem); }void AIC24LINK_wait() {SEM_pend(⩓AIC24_ready_sem, SYS_FOREVER); }

Questions & Answers

what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, From matlab and simulink to real-time with ti dsp's. OpenStax CNX. Jun 08, 2009 Download for free at http://cnx.org/content/col10713/1.1
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