I'm having a problem with setting voltage from the MSP430 to a 5V input line. I'm using the op-amp setup as specified in section 5.1 of TI's application report "Interfacing the 3V MSP430 to 5V Circuits" with a TLC27L4CN, R3=320k (220k+100k), R4=1M, R5=750k. Without connecting to +5V IO lines, logic levels are converted nicely on both sides, so by itself, it works.
The problem starts as follows: The 5V input initially has a voltage of approximately 5V. MSP430 outputs logic low and the 5V logic should be pulled down to 0V but it doesn't. It stays at about 5V. If I remove the jumper line from the 5V input pin and measure its voltage, it reads as about 0V. The conversion still works but the 5V input is not being pulled dragged for some reason.
Just for more information, these 5V lines are Data and Clock lines of a PS/2 mouse, which are initially set to high.
So why are the lines not being pulled down when the output voltages are 0V? Does the problem come from the op-amp, resistor values or is it just not possible in this case?