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LDC1612EVM: Zero MSB & LSB Data on LDC1612EVM design on custom board

Part Number: LDC1612EVM
Other Parts Discussed in Thread: LDC1612,

Hello, 

We purchased an LDC1612EVM board and got it working nicely. We took the LDC1612 and coil design from the LDC1612EVM board and placed it on our own custom board.

The issue is we're getting all zeros for the data.  

We followed Section 8.2.4 Detailed Design Procedure of the LDC1612 datasheet and used the same register settings from the EVM. The EVM produces data around 19 to 20 million, while our board produces all zeroes.

We have confirmed the registers written in 8.2.4 by simply reading them back. We program these registers with the values shown below. We're only using CH0 at this time

void ldc_init(void)

{

//these values were taken from the EVM

ldc_write_register(0x14,0x1001); //1. write ch0 clock dividers

ldc_write_register(0x10,0x0400); //2. write ch0 settling time

ldc_write_register(0x08,0xffff); //4. write ch0 conversion time

ldc_write_register(0x19,0x0001); //5. write error cfg reg to enable INTB DRDY

ldc_write_register(0x1e,0xf000); //6. write ch0 current drive (IDRIVE0)

ldc_write_register(0x1b,0x820c); //7. write MUX_CONFIG register

ldc_write_register(0x1a,0x1e01); //8. write CONFIG register

}

CH0 data is read as shown below, but they have only been giving us a value of 0 on our custom board.

This same code was used on the EVM's LDC1612 and coil breakoff portion, so we're confident these settings and code works.

uint32_t ldc_read_ch0(void)

{

uint16_t data_msb_ch0=ldc_read_register(0x00);

uint16_t data_lsb_ch0=ldc_read_register(0x01);

return ((((uint32_t)data_msb_ch0)<<16)|data_lsb_ch0);

}

Im adding a screenshot of the schematic 

3D Altium view showing the coil, identical to one on the LDC1612EVM

Any insight or guidance as to why our custom board is producing 0 data is greatly appreciated