Is there a way to disable the command character?
I want to guarantee I can’t enter command mode by accident after millions of hours of sending random data.
Ideally, I would want to be able to only set command-mode/passthrough mode by setting a GPIO pin high/low. I would imagine this would be a hugely popular interface model so I’m unsure why I can’t find this in the user guide.
Actually you are the first I have ever heard of that asked for this.
Generally the command mode sequence must be met in order to enter command mode. So in most cases, this does not occur without being deliberate.
That is, if you are worried about sending three plus characters in a row and have both Guard times met before and after, then change the command mode character.
I am transmitting intermittent bursts of random binary (not ascii) data. So, once I have 2000 out in the field I imagine it would actually be quite easy to trigger this by accident a couple times a month. I can waste bytes ensuring that this sequence never happens but it isn’t really “transparent” (or handy) if I need to make special exceptions for this module and then I have to make a different exception for another module. But I guess the answer is that it can’t be done. Thanks.
I really would not worry about it. In order to Enter command mode, you must first meet the command mode of silence on the UART, you then must issue the command mode character three times within the command mode of silence followed by the command mode of silence on the UART. That means by default, you need to have 3 seconds of silence, followed by three pluses in a row issued within three seconds followed by three seconds of silence on the UART. Then and only then will it enter command mode. Sending a random string of 2000 bytes or characters will not meet that sequence.