Hi,
There is something wrong in reading data from ads1278 in Frame-sync mode.
Firstly, the configures are listed as table 1. And scope of SCLK, FSYNC, DOUT1, DATA_IN is pictured as figure 1.
| FORMAT[2:0] | 011 |
| MODE[1:0] | 00 |
| PWDN[8:1] | 00000001 |
| FCLK | 25M |
| CLK | 6.25M |
| Vref | 2.5V |
tabel 1
figure 1
The problem is that when DATA_IN is +2.5V, the date that i read is 0x031000, not like the datasheet is 0x7fffff; And DATA_IN is -0.5V, the date that i read is 0x327100. So in this situation i can't identify the positive or negative of the DATA_IN voltage. And the data that i read is very steady.
In order to apply more information, the data of different DATA_IN is listed as table 2.
| DATA_IN | data |
| 2.5V | 0x031000 |
| 2V | 0x348000 |
| 1.5V | 0x675000 |
| 1V | 0x9a6000 |
| 0.5V | 0xcd3000 |
| 0V | 0xff2000 |
| -0.5V | 0x327100 |
| -1V | 0x65a000 |
| -2V | 0xca6000 |
| -2.5V | 0xfca000 |
