On XDS100v1 design, what does the OE signal do?
• A: On the XDS100v1 design, this OE signal on pin 12 of the FTDI chip comes from the ICA3A device (74HC74, flip flop). The ICA3A/IC1A section of the circuit samples the TVD signal to detect whether there is target power. This signal is read by the debugger via the GPIO on the FTDI. This signal has an opposite signal /OE which goes to U3. U3 provides a buffer which performs the voltage translation.
