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???
06/15/05 23:45
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#95050 - Combined Watchdogs
Responding to: ???'s previous message
Kai Klaas said:
By the way, why not combining both watchdogs, the internal and the external one? Ever done this?

I have done this for debug purposes with the Triscend E5 (now Zylogic ZE5):

The trouble with an external watchdog (WD) on an E5 is that it doesn't get "kicked" during JTAG downloads, or while the chip is stopped by JTAG debug - so an external WD disable is required for these situations. Enabling the internal WD in these circumstances allows the WD functionality and JTAG download & debug to be used together.

As I mentioned earlier, the trouble with the E5's internal watchdog is that it has to be explicitly enabled by the software - so it can't recover from situations where the software fails to start properly. This is a particular problem for the E5, since the startup process has to load the FPGA config before the software can even start running...




List of 25 messages in thread
TopicAuthorDate
AT89C51RD2 without supervisor IC            01/01/70 00:00      
   RC is never good            01/01/70 00:00      
      watchdog ad absurdum            01/01/70 00:00      
         and uses a bunch of pins            01/01/70 00:00      
            wd            01/01/70 00:00      
               paranoia revisited - wd 2            01/01/70 00:00      
                  when the full story            01/01/70 00:00      
                     WD3            01/01/70 00:00      
                        if code run astray            01/01/70 00:00      
   Has been discussed before            01/01/70 00:00      
   External ones are better            01/01/70 00:00      
      External ones are better in one respect            01/01/70 00:00      
         Yes, but...            01/01/70 00:00      
            Nope, never use an external when            01/01/70 00:00      
               Exactly!            01/01/70 00:00      
            Combined Watchdogs            01/01/70 00:00      
      External better in another respect            01/01/70 00:00      
   I'm using the internal and works well            01/01/70 00:00      
      works well - how do you know            01/01/70 00:00      
         who should test it?            01/01/70 00:00      
   nobody            01/01/70 00:00      
      the manufacturer should            01/01/70 00:00      
      Design Verification            01/01/70 00:00      
         one off            01/01/70 00:00      
      The meaning of "well"            01/01/70 00:00      

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