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good thinking.? pretty much exactly what Jack Ganssel said in the OP link http://www.ganssle.com/watchdogs.htm I hope everyone will read this and take a few lessons.? Jack is absolutely the premiere

All my satellites and other APRS projects (and TT4 modules) use an external watchdog timer made from a simple 555 timer chip. I just set the RC to time out in 90 seconds. And then the restart RC to

The ATMEGA has a watchdog timer built in. Which should be just fine for detecting hung code. One would think so, wouldn't one? Byon could doubtless address that better, but the illusive hanging

The ATMEGA has a watchdog timer built in. Which should be just fine for detecting hung code. Not the greatest which reminds me of a web page I ran across years ago:

The chip is for TTL to RS232 for the serial port. Once you use the erial port to configure the digi, then the serial port at a digi is not likely used... Unless you are using a CPU to send the various

All 4 that we have are used as digis. All 4 are set to Tx their DC voltage so we can monitor the status of power supplies, back up generators, solar panels, & batteries. We use AGM batteries and can

All of my Projects at the Naval Acadmy and our satellite designs, PSAT2 (on orbit) use the MTT4B basic system, but the first thing we do is remove the MAX232 chip since its internal buck/boost

Watchdog timers are awesome and easy to implement internally in most any micro. Here is an external one in an old-fashioned dip: https://www.mouser.com/ProductDetail/998-MIC1832NY As Barry pointed

Rob, The MTT4BT-40 is much the same as the original MTT4B, we just decided that all the MTT4BT's would have the Bluetooth Module instead of having to stock four different varieties of MTT4BT's ( Low

I am not sure what the MT4BB is? If it really "IS" the max232 chip, and the MAX232 chip is in a socket (MTT4B and kit TT4), I suggest removing the chip and interfacing with the unit through TTL

Dave, The MAX chip has built-in pull-ups, and a bunch of people have tried adding external pull ups or pull downs with out any clear resolution. The problem is so intermittent, that its very difficult

The problem with having a TT4-based watchdog timer is that the ATMEGA chip seems to be the thing that hangs, so depending on the code to run in the chip that is locked up is a no-go. I have considered

If you are OK with the fixed periodic reboot solution, the following might still be useful in the future. Google "Watchdog Timer," the time-honored, last-ditch method of dealing with many

Done that. Found nothing. The timer work around works. Not worth spending any more time on the issue. -- Compton VK2HRX Sydney, Australia

An open input might be asking for trouble. On something where the serial port isn't being used, a connector wired to pull the input to a known state might help. Putting one of the problem systems in a

Hi Allen, We selected once a week as the units have always lasted between 1-3 months before hanging. We could do it daily or even hourly but once a week works. There has only been a single episode

Compton, Why not reset the timer more often? (Every day?) Are you finding that once a week is enough to keep the units running reliably? Our problem is not being able to replicate the hanging

Danny, correct, hasn't been used in a while so i tested both before and after a factory reset with same results. I suspect, as suggested by Rob, there may be an interface problem. The radio is always

I am in a group in Sydney that uses 4 of these. We experence the same issue. We ended up fitting a timer that turns the power on/off. We set the time to do this every Tue at 2AM. If they happen to go

About the only 3 'internal' things that would provide no audio are:?* The TX potentiometer R1?* JP8 installed.? This is only needed for "some" HTs.? Not with radios using the Data Port.?* TX amp