Question: I have noticed that after I modify the Settings using the “S” command (i.e. “SBR3” to change the baudrate) the changes do not have immediate effect. When do the changes take place? Is there a way to make those changes have immediate effect?
Answer: The changes you make to most Settings are immediately recorded into the non-volatile memory (EEPROM) of the DS100/EM100 but only take effect after you REBOOT the device- by power-cycling it or by using the “E” command (“O” command won't do this for you because it merely ends the programming session without rebooting the device). For serial port parameters (baudrate, parity, etc.) there is a way to change them without rebooting the DS100/EM100. This is done through the “P” command (i.e. “PBR3”). Changes made this way have immediate effect but they are not lasting – a new value is NOT recorded into the EEPROM and is “forgotten” once the DS100/EM100 is switched off. When the device is powered on the serial port will once again use “permanent” parameters that are stored in the EEPROM.
There is a good rationale for why we have designed the DS100/EM100 this way. As you probably know the EEPROM is an imperfect device – it has a limited number of write cycles. Changing the data in the EEPROM too often will eventually wear it off and the device will start malfunctioning. So, we have provided two different commands. “S” command saves the data into the EEPROM. You use it to define a permanent configuration for the DS100/EM100 (that is not changed so often). If you need to change some parameters often, you use “P” command which has immediate effect but does not write anything into the EEPROM (and hence, there is no danger of wearing it down).
