|
Hi all, I have a c6711DSK, and I'd like to transfer signal information from my DSK to my PC. I'm working with the TI aic23evm codec. This is a 16bit two channel DAC and two channel ADC. I'm currently taking a signal from one of the ADCs, processing this signal, and outputting the resultant processed signal to the DAC. I'd now like to transfer the processed signal to my PC also, so I can store it as a wav file and display it on screen. I'm implementing my Codec communication using PIPes and EDMA. I have two PIPs, for rx and tx respectively, with 4 frames each and a frame word size of 128. My code includes the following SWI - Void AudioSWI(PIP_Obj *in, PIP_Obj *out) { Uns *src, *dst; Uns size; Uns f1,f2; //each channel in floating point form Uns size; size = getBuf(in, &src); // size = 128 allocBuf(out, &dst); for (i = 0; i < size/2; i++) { // channel 1 and 2 stored as 32-bit; convert to float UnsToFloat(*(src+i),f1,f2); f1 = process(f1); // process channel 1 sample FloatToUns(*(dst+i),f1,f2); } putBuf(out, size); freeBuf(in); } How should I transfer each of the samples, f1, to my PC using HPI? I could create a large buffer and fill it with each sample, and notify the PC when it is filled. The PC could then start reading this buffer - but the DSP cant write the buffer until the PC is finished reading, which complicates things. What size should I make the buffer? Do I really need to implement HPI interrupts, I've had problems doing this before... Would handshaking suffice instead, with out impacting on efficiency to greatly? I could set aside a memory address where both the PC and DSK read and write flags. This is what I've done in the past. I can think of ways of doing this, but I'm sure there is a more efficient method. Thanks very much for your help, Fran. |
|
|
sending a signal to a PC via HPI
Started by ●January 25, 2004
Reply by ●January 26, 20042004-01-26
|
What Type of sample rate are you trying to maintain? Try using a "ping-pong" buffer for the data you are sending to the PC, so that a PC interface process can be reading data from one buffer while the DSP data acquistion and processing thread can write data to the other. If you've got enough MIPs, you'll be able to do it at your intended sample rate. Also consider using TI's RTDX approach, but again you may have throughput problems. We've implemented a similar functionality using a 5510 DSK in our "Hard Disk Recorder" (see our web site), we record audio data straight to a harddrive. We could probably use this experience to get a similar system to work on a 67. We are available for more consultation & engineering services. Contact us if you're interested. -Shawn Steenhagen www.appliedsignalprocessing.com --- In , "rockall_rebel" <rockall_rebel@y...> wrote: > Hi all, > > I have a c6711DSK, and I'd like to transfer signal information from > my DSK to my PC. I'm working with the TI aic23evm codec. This is a > 16bit two channel DAC and two channel ADC. I'm currently taking a > signal from one of the ADCs, processing this signal, and outputting > the resultant processed signal to the DAC. I'd now like to transfer > the processed signal to my PC also, so I can store it as a wav file > and display it on screen. I'm implementing my Codec communication > using PIPes and EDMA. I have two PIPs, for rx and tx respectively, > with 4 frames each and a frame word size of 128. My code includes the > following SWI - > > Void AudioSWI(PIP_Obj *in, PIP_Obj *out) > { > Uns *src, *dst; > Uns size; > Uns f1,f2; //each channel in floating point form > Uns size; > > size = getBuf(in, &src); // size = 128 > allocBuf(out, &dst); > > for (i = 0; i < size/2; i++) > { > // channel 1 and 2 stored as 32-bit; convert to float > UnsToFloat(*(src+i),f1,f2); > > f1 = process(f1); // process channel 1 sample > > FloatToUns(*(dst+i),f1,f2); > } > > putBuf(out, size); > freeBuf(in); > } > > How should I transfer each of the samples, f1, to my PC using HPI? I > could create a large buffer and fill it with each sample, and notify > the PC when it is filled. The PC could then start reading this > buffer - but the DSP cant write the buffer until the PC is finished > reading, which complicates things. What size should I make the > buffer? Do I really need to implement HPI interrupts, I've had > problems doing this before... Would handshaking suffice instead, with > out impacting on efficiency to greatly? I could set aside a memory > address where both the PC and DSK read and write flags. This is what > I've done in the past. > > I can think of ways of doing this, but I'm sure there is a more > efficient method. > > Thanks very much for your help, > > Fran. |
