peppe,
i think that you're missing something here. please read the code
carefully: if the current buffer is 0, then where was the most recent
data written?
another thing to consider is that you want to do as little as possible
in interrupt context (e.g. async events). adding a memcpy there is not
advisable unless it's absolutely necessary (it's not).
you'll also have to change the code that "prepares" the radio packet. i
should point out that accelecg goes to a lot of trouble to build up a
packet with data that you don't really need; you might want to consider
using SimpleAccel as the basis for your development instead. it will be
much easier to modify correctly, it transmits only sampled data, and it
will be much more power-efficient than accelecg as it buffers 20 samples
together in one transmission rather than sending a packet for each sample.
-steve
On 10/06/2011 04:46 AM, Peppe Scabellone wrote:
Thank you both for answering.
So, if I need to capture the datas from the two ecg channels I only need
to call
call shimmerAnalogSetup.addECGInputs();
call shimmerAnalogSetup.finishADCSetup(sbuf0);
in the Init() and then:
async event void DMA0.transferDone(error_t success) {
if(current_buffer == 0){
call DMA0.repeatTransfer((void*)ADC12MEM0_, (void*)&sbuf1,
NBR_ADC_CHANS);
memcpy(ecgData, &sbuf1, sizeof(*sbuf1)*NBR_ADC_CHANS);
current_buffer = 1;
}
else {
call DMA0.repeatTransfer((void*)ADC12MEM0_, (void*)&sbuf0,
NBR_ADC_CHANS);
memcpy(ecgData, &sbuf0, sizeof(*sbuf1)*NBR_ADC_CHANS);
current_buffer = 0;
}
without making the
call shimmerAnalogSetup.addAccelInputs();
in this way in the array ecgData I will have the datas from the two
channels?
2011/10/5 steve ayer <[email protected] <mailto:[email protected]>>
hi peppe,
for the record, i did not write this application, adrian burns did.
i made a few latter-day mods to clean it up after creating a
component for all of the analog-digital setup and conversion
functionality.
p_packet is a local variable used to walk the buffer that the
bluetooth radio will send; it was not meant to be visible elsewhere.
the buffer that it references is.
as for "calling" transferDone, you don't call events; they are
signaled from modules that are performing an operation to notify the
receiving code that something related to an interface that it uses
has happened (tinyos is an event-driven operating environment).
finally, this application works splendidly and has been in use --
deployed clinically -- for a number of years. to get the data from
the ECG, all you have to do is receive it over bluetooth on a host
computer.
if you're looking for the two ECG channels, by reading the comments
at the top of the file, you'll see a detailed description of the
radio packet's contents, which includes the size and location of all
of the data produced by this application, in order to make it very
simple to parse the incoming data on the host side.
-steve
On 10/05/2011 06:55 AM, Peppe Scabellone wrote:
Hi , I was looking Steve Ayer's AccelECGC.nc file.
I need to get datas from ECG and as I can see in that file the real
datas are stored in p_packet array as you can see below:
/* copy all the data samples into the outgoing packet */
*p_packet++ = *p_ADCsamples++; //tx_packet[8]
*p_packet++ = *p_ADCsamples++; //tx_packet[10]
*p_packet++ = *p_ADCsamples++; //tx_packet[12]
*p_packet++ = *p_ADCsamples++; //tx_packet[14]
*p_packet = *p_ADCsamples; //tx_packet[16]
but this p_packet is never used in other part of the code.
I need the two channels of ECG stored in one array
uint16_t ecgData[2]
so if I call
async event void DMA0.transferDone(error_t success) {
if(current_buffer == 0){
call DMA0.repeatTransfer((void*)__ADC12MEM0_,
(void*)&sbuf1,
NBR_ADC_CHANS);
memcpy(ecgData, &sbuf1, sizeof(*sbuf1)*NBR_ADC_CHANS);
current_buffer = 1;
}
else {
call DMA0.repeatTransfer((void*)__ADC12MEM0_,
(void*)&sbuf0,
NBR_ADC_CHANS);
memcpy(ecgData, &sbuf0, sizeof(*sbuf1)*NBR_ADC_CHANS);
current_buffer = 0;
}
post preparePacket();
}
and the method
void preparePacket() {
uint16_t *p_packet, *p_ADCsamples, crc;
p_packet = (uint16_t *)&tx_packet[8];
if(current_buffer == 1) {
p_ADCsamples = &sbuf0[0];
}
else {
p_ADCsamples = &sbuf1[0];
}
/* copy all the data samples into the outgoing packet */
*p_packet++ = *p_ADCsamples++; //tx_packet[8]
*p_packet++ = *p_ADCsamples++; //tx_packet[10]
*p_packet++ = *p_ADCsamples++; //tx_packet[12]
*p_packet++ = *p_ADCsamples++; //tx_packet[14]
*p_packet = *p_ADCsamples; //tx_packet[16]
}
The Question is using these two methods I'll have the datas in
ecgData
array? or I have to intercept p_packet?
Thank you.
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