PGA309: Register 7

HI Guillaume,

Register 7, Output Enable Counter Control Register, is documented on page 89 and page 116 of the PGA309 User Guide. 

This register is primarily used during the calibration process, prior programming the EEPROM with device settings and calibration coefficients, and is mainly useful for applications using One-Wire Operation with PRG connected to Vout during the calibration process.  It allows a multiplexing operation between PRG using the connection as a bidirectional interface and  Vout driving the connection as a conditioned sensor output voltage.

The register controls the timeout delay for VOUT enabled.  For the PGA309 + sensor calibration, it is necessary to configure and reconfigure internal registers on the PGA309 and then measure the analog voltage on VOUT as a result of these register value settings. Therefore, to do this while VOUT is tied to PRG requires the ability to enable and disable VOUT.

The User Guide recommends storing invalid data in the programmed flag values of the EEPROM while performing this calibration process, to prevent  the EEPROM from being read, which could change the register settings in the PGA309. It also forces the one second timeout to be reset and allow as long as needed for communication to start and stop on PRG. Once all registers in the PGA309 have been set to their desired values, another write to Register 7 will start the process all over again so a new analog value of VOUT can be measured.

Thank you and Best Regards,

Luis