Hi Tom Your problem is not uncommon and in my experience I prefere to use a seperate Brown out detector to control the Reset of any processor that I'm using. My main reason is that it provides a definte cut-off point and operation which gives me predicted soft start and brown out conditions.
There are many ultra low power devices avalible with a Iq in the order of 1uA. This is fine for critical battery based equipment. In SOT-23.5 TPS3837L30 is one such part. For most designs I use a MAX 809 or equivalent and have found this to be very reliable. Regards Mike Kroon ----- Original Message ----- From: "Tom Russell" <tcruss...@ieee.org> To: <mspgcc-users@lists.sourceforge.net> Sent: Friday, August 22, 2003 10:13 PM Subject: [Mspgcc-users] brown out reset > I have a circuit with the MSP430F133 that needs brown-out reset. If the > power is disconnected for a short time, but not long enough for the voltage > to decay to near-zero, I don't get a POR when power returns and the program > goes to an unknown state. I could monitor the voltage and when it gets low > generate a POR by pulling RST low or a PUC by writing an exception to the > WDT. The problem is that the unit will then continue to operate from that > point until the voltage falls low enough to mess it up and then I still > don't think I can be sure what happens when power is restored. I don't > think using the comparator helps because its control register will also > become undefined as the voltage drops. > > Of course I can add an external voltage comparator connected to the reset > pin, but anyone have a software solution? I know some MSP parts have BOR > (brown-out reset), but strangely not all. > > Thanks for any suggestions, > > Tom Russell > > > > > ------------------------------------------------------- > This SF.net email is sponsored by: VM Ware > With VMware you can run multiple operating systems on a single machine. > WITHOUT REBOOTING! Mix Linux / Windows / Novell virtual machines > at the same time. Free trial click here:http://www.vmware.com/wl/offer/358/0 > _______________________________________________ > Mspgcc-users mailing list > Mspgcc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mspgcc-users
