I have a battery-powered standalone arduino project that stores some data to its SRAM. I will need to connect it to FTDI to upload data to PC. I can't power it down as the content will be lost. So while it's powered by battery, I will connect its RX, TX, GND, RST to the FTDI (basically my deumilanove with its atmega removed). This is ok right now but if I use an FTDI USB cable (http://www.sparkfun.com/commerce/product_info.php?products_id=9718) to tidy my project then I will have to disconnect the 5V on the cable, right? Or otherwise I connect the 5V from my standalone with the 5V on PC the battery may die.
Am I correct? Thanks.