Re:Another Serial Port Question

[MarkO]

@rconn14

Hi,

All postings on this forum that I’ve come across, including the discussion in the FAQ, seem say that both of the serial ports (the one on the “back” of the controller next to the RX2 port, AND the RX/TX port on the i/o ports) are TTL serial ports… unless I am misinterpreting them. On the Vex processor specs, though, (http://www.vexrobotics.com/vex-robot…-system.shtml), the serial ports are listed as:

Serial Ports: RS232 Program (115Kb) and TTL Serial (115Kb) - RX and TX on Digital/Analog port

Does this mean that the RX/TX serial port on the top of the processor is TTL, but the serial port on the back of the processor (next to “RX2”) is rs232?

Thanks!

No. Both Serial Ports are TTL. When you use the Vex Programming Cable or a 3rd Party TTL-RS-232 converter, you then make the Serial Port accessible with RS-232 hardware.

The signal level of the UART is 0 Volts for a Logical Zero and +5 Volts for a Logical One. Depending on how that Signal needs to be transmitted to another device, you would then connect the UART to a Transceiver for RS-232, RS-422/RS-485 or maybe even a Fiber Optic connection.

I found this link at Wikipedia, [/FONT]MICROCONTROLLER UART TUTORIAL.