In our system we are using the PGA309 frontend anr we control it trough a microcontroler with the One-wire Interface.This all works fine, till we enable bit15 register 4 and then disable it again and flash this in the EEPROM.After this the PGA309 does not response to any question. Can't read registers and eeprom any more.How can we recover from this state?
Programming on OMAP L138, LogicPD evm board
Hello Royke,
The short answer is that once setting the One-Wire-Disable (OWD) bit, you must cycle power to the PGA309 before you can communicate again.
Are you using 3-Wire (One-Wire-to-Vout) mode with your PGA309 design? If not, then it should not be necessary to set the OWD bit. If so, then you must follow the proper timing requirements while in this mode.
The procedure for communicating while in this mode is as follows (refer to the PGA309 User's Guide, section 4.10 for more information):
Best regards,
Ian WilliamsLinear Applications EngineerPrecision Analog and Sensing Products
Thanks Ian for you reaction.We are using the 4.3 One-Wire Interface, so not through One-Wire-to-Vout.I know we don't have to set the OWD bit, but we did. (It was available through the user interface) So the OWD-bit affects also our 1 wire interface. Now I have 3 sensor-modules that I can't use and I would like to use them again.Can I do this by following you described procedure?Also what is the CMD WAKE_UP_ONE?
Royke,
Correct, the OWD bit affects the One-Wire interface. If you set the OWD (One-Wire-Disable) bit, that disables the One-Wire interface communication and places the PRG pin in a high-impedance state. The exception is for 25ms after powering up the device.
The "CMD WAKE_UP_ONE" is a command which cycles power and writes to the device during the 25ms waiting period. This command can only be given when using the PGA309EVM.
To re-establish communications with your modules, simply cycle power to them and perform any One-Wire communication within 25ms. This will allow further communications for up to 1s, and during this time you can clear the OWD bit, clear the EEPROM, and perform any other necessary transactions.
Ian Williams
Thanks again Ian for your clear answer.I know what to do now.
You're very welcome.
One final note - it may be desired to set the OWD bit once you have finished communicating and calibrating the modules and they are ready to go into their end system. This is because noise can couple into the system from the outside world which may look like communication attempts at the PRG pin. This can cause issues as you might expect. Setting the OWD bit and placing the PRG pin in a high-impedance state prevents this. We refer to this as "stand-alone operation."
Thanks Ian,One final note from me, we completely control the PGA309 in the machine through a microcontroler including the setup. So we wouldn't set the OWD-bit.
Again thanks for your support!
Thank you for the clarification. I'm happy to help.