Scott W Harden writes , “The FT232 USB-to-serial converter is one of the most commonly-used methods of adding USB functionality to small projects, but recently I found that these chips are capable of sending more than just serial signals. With some creative programming, individual output pins can be big-banged to emulate a clock, data, and chip select line to control SPI devices.
This post shares some of the techniques I use to bit-bang SPI with FTDI devices, and some of perks (and quirks) of using FTDI chips to bit-bang data from a USB port. ”
See the full post on Scott Harden’s blog .
Check out the video after the break
A bit sad that you are using a knock off Saleae device unless you are not using Saleae software.
Also interesting to note that arduino’s use the DTR signal to reset the device. I found this out because repetier was able to do this with a marlin firmware on Arduino 2560. Not all usb to serial chips have this signal as an output pin though. I wanted to send gcode through my own program in c#.
While it is a thorough description, bitbang serial programming is nothing new.
http://nerdralph.blogspot.com/2014/05/pl-2303hx-bit-bang-avr-programmer.html
For those who don’t want to modify a pl2303hx, CP2102 adapters with pins/pads for DTR, RTS, etc. can be foumd for $1 on Aliexpress. FTDI is way overpriced in comparison.