3.b. Logic Connections
The qik requires a logic-level (0 – Vcc), non-inverted serial input connected to its serial receive line, RX, and it can handle baud rates from 1200 – 38,400 bps. This type of serial is often referred to as TTL and is an interface method commonly used by microcontrollers. The voltage on this pin should not exceed the supplied logic power voltage, Vcc. The qik provides logic-level, non-inverted serial output on its serial transmit line, TX, in response to commands that request information. Information requests always result in the transmission of a single byte per request. If you aren’t interested in receiving feedback from the qik, you can leave this line disconnected.
Note that these lines are not compatible with RS-232 serial, which is inverted and uses voltages that would be out of spec (e.g. -12V to 12V). To connect the qik to an RS-232 port, you must use a converter such as our 23201a serial adapter, or a level shifter and inverter.
The reset line, RST, is an active-low input, which means that it resets the qik when driven low. This pin is internally pulled to Vcc, so many applications can leave this pin disconnected.
The error line, ERR, is an output that is connected to the red error LED and drives high (Vcc) in response to an error (which in turn lights the LED). Once an error occurs, the pin outputs high until a serial command is issued to read the error byte, at which point the pin goes to a high-impedance state that is pulled low through the LED. This allows you to connect the error lines of multiple qiks to the same digital input. Please note, however, that doing this will cause the error LEDs of all connected qiks to turn on whenever one qik experiences an error; the ERR output of the qik experiencing the error will drive the LEDs of any other qiks it is connected to, even though they are not experiencing error conditions themselves. For more information on the possible error conditions, please see Section 5.b. If you don’t care about error detection, you can leave this pin disconnected.