41CL News

[Monte Dalrymple]

I should point out that Compare-Only mode has the potential to cause problems in some corner cases. For example, since the FLDB is stored at 0x0DE in Flash, if an update is aborted after the FLDB has been written but before the entire Flash has been updated, the non-updated Flash pages will be stale relative to the FLDB contents. If you use CPONLY during the next update, those stale pages will not be updated. There is a simple way around this, which is to always make sure that an update completes, even if you have to restart it after it has been aborted. An update can be aborted from the keyboard, because of a timeout during a serial transfer (which happens all the time to me as my PC ignores the keep-alive bytes and goes to sleep aggressively), or because the battery level has fallen too low. Even though an update has been aborted, the CFLDB in RAM is still valid, so the update can be restarted even if you have to change batteries. I have done this several times. The RAM has always retained its contents during the battery switch-over, but I am always careful to do it as quickly as possible.