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ADAS1000 - Getting strange values during the QRS peak!!!

Question asked by Sagong on May 29, 2013
Latest reply on Aug 2, 2013 by CatherineR

Hi, I'm using the ADS1000 targeting two kind of medical equipment, an ECG Holter and a High end Electrocardiograph. At this moment I'm using the ADAS1000SDZ Evaluation board with a custom board with a MSP430F5529 running at 18.0MHz. I started my firmware development form the one posted at http://wiki.analog.com/_media/resources/tools-software/uc-drivers/renesas/adas1000_rx62n.zip making the needed modifications. At this moment I can write and read adas1000 registers correctly and read the data frames.

My curent configuration is:

 

ADAS1000_Init(ADAS1000_2KHZ_FRAME_RATE); 

ADAS1000_SetRegisterValue(ADAS1000_ECGCTL,      0xF800BE);

ADAS1000_SetRegisterValue(ADAS1000_CMREFCTL,    0xE0000B);

ADAS1000_SetRegisterValue(ADAS1000_FRMCTL,      0x079000);

 

I'm only interfacing with the master chip in the ADAS1000SDZ board, and filling the the next structure with the frame information;

// long int is 4 bytes for MSP430!!

typedef struct ADAS1000_Data_Frame

{

          long int Header;                    /* Frame Header */

          long int Lead1_LA;          /* ECG Lead 1 / LA */

          long int Lead2_LL;          /* ECG Lead 2 / LL */

          long int Lead3_RA;          /* ECG Lead 3 / RA */

          long int V1;                              /* ECG Lead V1 */

          long int V2;                              /* ECG Lead V2 */

          long int Pace;                    /* Pace */

          long int RespMag;          /* Respiartion Magnitude */

          long int RespPha;          /* Respiration Phase */

          long int Leads_Off;          /* Leads Off */

          long int GPIO;                    /* GPIO */

          long int CRC;                    /* Frame CRC */

}ADAS1000_Data_Frame;

 

I uploaded an excel file with graphs showing the problem that I'm facing.

Basically I get a clean signal (even with JTAG connected to the MCU), but on the top of the QRS complex I get extremely low values (like sign inversion effect). This is happening with all the other leads too. I know for sure that I'm losing frames but still I think this is not related to the problem I'm facing (I will move to another low power MCU in future looking for more RAM and speed for 12 lead HPF, any suggestion will be appreciated).

The kit is working fine with the Blackfin board (only some noise in the slave related leads but this is not important at this moment).

I know there should be some miss-configuration somewhere but I just can't see it.

 

Thanks in advance,

Sagong

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