alter-jx38
Newbie
Hi guys. I was faced with the task of inverting TTL signals to a different logic and can't get how to did it correctly.
I have a dive-computer with communication interface that interprets LOW= +3V and HIGH= 0V. It has an internal pull-up resistor of about 12k, which is connected to the internal supply of 3.0V
Since the device already has a pull-up resistor, a relatively large pull-up resistor in the pc-interface can be used, since this resistor is only needed to keep the data line in a defined state (high) when the dive-computer is not yet connected.
To connect him I suppose to use simple UART-USB controller based on CP2102 with ordinary TTL logic where LOW is 0V and HIGH represented by +5V. The communication is pretty slow with 1200 baud, 8 bits, 1 stop bit and no parity.
I'm guessing there should be a few NPN transistors but can't realise exactly how?
I have a dive-computer with communication interface that interprets LOW= +3V and HIGH= 0V. It has an internal pull-up resistor of about 12k, which is connected to the internal supply of 3.0V
Since the device already has a pull-up resistor, a relatively large pull-up resistor in the pc-interface can be used, since this resistor is only needed to keep the data line in a defined state (high) when the dive-computer is not yet connected.
To connect him I suppose to use simple UART-USB controller based on CP2102 with ordinary TTL logic where LOW is 0V and HIGH represented by +5V. The communication is pretty slow with 1200 baud, 8 bits, 1 stop bit and no parity.
I'm guessing there should be a few NPN transistors but can't realise exactly how?