Remote reset?

[James Harland]

Hello everyone,

I currently have my RC 2014 Classic ][ attached to a Linux netbook at home which is also my family's printer server. This means I can log into it from the home network, or from the conected terminal. But in any case I have to physically press the reset button to get into BASIC or the monitor once I have opened Minicom. 

I am wondering if there is any way round having to press this button to reset, short of some kind of home automation? Is there any way of sending the RC 2014 a signal from the computer which will reset it?

Thanks,

James

[Jonathan Harston]

The docs say the serial port uses a 6850. Is there a way for the serial interface
to detect a line break, and wire that to the reset circuitry? Then you could reset
the RC2014 by sending a line break.

[aaw...@gmail.com]

gl-inet has a fingerbot.  It's a little box to use with their KVM.  When activated, a finger reaches out and presses the reset button.  It talks to the KVM wirelessly.  I don't know if it is via infrared or radio.   I have one I use with a KVM for a PC.  But I haven''t tried hacking it to use it without the KVM.

https://store-us.gl-inet.com/products/fingerbot

[Phillip Stevens]

If you search for RESET in this Group there are quite a few good idease available. Back in 2019 I remember someone bodged in a transistor driven by the /DTR signal generated by the FTDI adaptor. Generally using /DTR is a good way to go, as there are plenty of scripts available from within the Arduino community, and from here.

 

[Andy Nicol]

My solution might be overkill, but I use a Raspberry Pi board with WiFi to communicate to my RC2014. I fitted a BC Robotics relay hat to it, and I have a script which runs from .bashrc to pulse a relay and reset the RC2014 when I log in remotely from my desk. The relay is connected to the reset circuit on the RC2014. No doubt an opto-isolator would have done, but it is what it is, and it works.

[Greg Holdren]

I had been thinking of sometime similar lately myself. But what would be nice is having something small that is on the net but wireless and I do have these cheap ESP8266 modules just sitting around. One of the reasons to pull on the reset line is when code that goes off into the weeds and you are remote. This will get you back to the boot loader or monitor.

An example of project for this:

https://randomnerdtutorials.com/esp32-esp8266-web-server-outputs-momentary-switch/

Greg

[Jonathan Harston]

I started sketching something out and it looked familiar. Digging through some old notes I found some notes I'd made on detecting a serial break at the hardware level.

* Serial idle is a constant '1' state.
* A serial frame is a '0' state, followed by up to nine '0' or '1' states, followed by at least one '1' state, then returning to the idle '1' state.
* To send a serial break the line must be held in the '0' state for at least two characters.

So, when no break is being received, the data line is either '1' (idle) or there will be at least one '1' in ten RxClock cycles - either a '1' bit in the data or the terminating '1' bit. When a serial break has been received the line has been held at '0' for at least 20 RxClock cycles.

So, use the RxClock to clock a counter, count up to 16 (nice binary number), resetting if an RxData '1' is received. If you have counted sixteen then you must have received sixteen '0's, so you must have received a break. This diagram probably won't come out right:

          +-------------+
RxCLK---->+CLK  divide  +----> BREAK
RxDATA--->+RST  by 16   |
          +-------------+
             eg 74LS93

Connect BREAK (inverted if needed) to the CPU RESET line,and you have a hardware watchdog triggered by receiving a serial break.

[Mark T]

A simple method might be to use a MAX818 or similar with a watchdog timer, this would only need a diode from the rx input to the watdog input. The break would hold the watchdog input and trigger the watchdog timer to reset the processor. The MAX818 would also replace the system power on reset and support battery backed sram for the ram disk. There are other devices with similar watchdog timers.