Hi,
We have the following design: 1 x ADS1298R and 1 x ADS1296 in daisy-chain (ADS1296 -> ADS1298R) and this is connected to a TMS320C5515 - EVM board.
We have started with the TI medical development kit as reference for our programming and modified it according to our above mentioned configuration and informations in the datasheets regarding daisy-chain.
Our problem is we can't get coherent data out of the daisy-chain. We tried the following:
- word len.: 24 with 17 frame len. (9 frames ADS1298R, 1 frame "don't care bit", 7 frames ADS1296) in one read cycle so the CS doesn't go high between the reads;
- word len.: 1 with 385 frames (216=(24*8)+24 frames ADS1298R, 1 frame "don't care" bit, 168 frames=(24*6)+24 frames ADS1296) also one read cycle (CS - low)
I don't seem to be able to get consequent data, the first byte in the SPIbuf (SPI buffer variable) seems to be the same most of the time but it also varies but not in a repetitive meaner. The rest is data the can not be viewed as ECG (we have our PC software that is tested with the ADS1298R EVM and data is OK).
Can you please provide some assistance regarding how should we design our data retrieval function, or perhaps we are doing something else wrong.
Thank you.
