Hello,
This is about the 4th tread I have opened and haven't got any answer. I have managed to solve some of the issues I have and I will keep posting my questions when I get stuck.
I am interfacing the 1298 with the FG4618. I am working with the ADS1298 PDK and the MSP430FG4618 Experimenter's Board. I have removed the MMB0 from the 1298 PDK and providing 5v and 3.3v from a power supply. The START, RESET and DRDY pins are controlled by the FG4618. The spi link happens though the USCIA0 module.
So far I can set the ADS1298 registers and read some data in continuous mode. In order to verify that the data I am reading is correct I am providing a VREF+ GND and VREF- to CH1 since I understand the dynamic range goes from VREF to - VREF. I am setting the registers as follows
CONFIG1 0x86
CONFIG2 0x00
CONFIG3 0XC0
The ADS1298 PDK jumper set up is the default set up. I am only using CH2, (normal electrode input and gain of 1),the others are shut down.
When I connect GND to the input I read 0X7FFFFF which should be the case for VREF reading. When I read anything between VREF and GND I get 0x7FFFFF and when I read -VREF i read a value close to 0x000000. I know that the maximum limit is -VREF-0.3V, from the datasheet, so I tried VREF-0.1/0.2 and the readings were 0xFE9323 and 0xFF2345. I wasn't able to get any reading closer to the ideal negavite value of 0x800000.
Can somebody give me advise on what I may be doing wrong? Or in any other way to test that the values are being read properly?
I hope I was able to express my questions properly, if not please let me know. Also if you need scope screen shots or the whole code please let me know.
Best regards,
Efrain