I am currently trying to interface a LD1100 laser driver from Thorlabs (http://www.thorlabs.com/thorproduct.cfm?partnumber=LD1100), to a GT16A micro, but am unsure of a few connections. Firstly there is an on/off control that is controlled by an open-collector, bipolar transistor. I have selected a BC817-25 transistor and have connected as shown below. Is the connection correct and would I need a resistor?
Secondly, the gain is adjusted by connecting several resistors to ground. These resistors interface with the GT16A through several pins from the LD1100 module. Can I connect each pin directly to the micro through a GPIO and the pull the GPIO pin high or low depending upon whether I want to ground the appropriate pin?
Thanks for all the help!