M Heimbach

Full Scale Range for A/D Converter

Discussion created by M Heimbach on Dec 29, 2009
Latest reply on Dec 30, 2009 by bigmac
Hi, I am using the HC9S08LG32 (SPI connection) to interface with the ADS1241, a 24-bit A/D converter.  The Vcc supply is 5V, while the Vref is 1.25V (Vref- is grounded).  My problem is that there's a 24-bit register in the A/D called FSR (Full Scale Register).  I am unable to figure out what 24-bit value to insert here.  The maximum voltage that the A/D would ready is about 50mV, so I'm programming in a gain of 16 to the A/D (which has an internal pre-amp).  I've been trying different values of FSR, but no luck.  Any inputs welcome, thanks.

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