Giray Hakan <[email protected]> writes: > We want to connect Telemetrum v2.0 "main" and "apogee" pins with our > MCU.
Easy. FYI, I'm CC'ing our mailing list so that a copy of this message
is in our archives for the use of others.
> We need to know apogee and main pins timing diagram how long its holding
> high/low state?
50 milliseconds with stock firmware.
> What is the Vout(min) and Vout(max) values?
> When we connects this pins with oscilloscope we didn't get any
> understandable output
That's because we're using a "low side switch", which is a switch to
ground on one side of the pyro device. You can look at the schematic to
see how this is wired, which you can find on our product info page at
https://altusmetrum.org/TeleMetrum
So .. for each pyro channel, there are two screw terminals. One is
fixed at v_pyro which is the LiPo battery through the power switch. The
other is a FET switch to ground. So what you want to do is ignore the
screw that is at v_pyro, and only use the screw that is attached to the
FET switch.
Connect ground on your MCU board to the ground on our board, which you
can find on the "extra hole" adjacent to the screw terminal strip, or
on any of the mounting screw holes.
Configure your MCU to have a pull-up on the desired input (may be
possible when configuring your GPIO pin to use an internal pull-up, or
you may need an external resistor, depends on your MCU).
Connect the screw terminal with the FET switch to ground to your MCU
GPIO input pin.
Now, you will see a high whenever nothing is happening, and the line
will be pulled low when the channel fires. Most MCU parts can trigger
an interrupt on such a state change, or you can poll the pins looking
for them to go low as you prefer.
The pinout of the screw terminals is like this, starting from the end
where the extra ground hole exists in the board:
v_lipo (output) side of power switch
plus terminal of LiPo (input) side of power switch
v_lipo side of MAIN pyro channel
FET switch to ground for MAIN
v_lipo side of APOGEE pyro channel
FET switch to ground for APOGEE
And yes, this means three of the screw terminals (every other one) are
connected to the the same net, v_pyro.
I hope this helps
Bdale
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