Of course it works. TFT32 and TFT28 have the same firmware. Marlin printer firmware don't send out board type (Ramps or other) in the connection response. Therefore even if TFT itselv want detect printer board, it can't. The problem is in the communication. First - You need separate power 5V supply (200 mA is enough), and then the TFT Tx output (connected to the AUX1 D1 pin) must have more energy set it to LOW signal. One tranzistor and rezistor solve it, or use any AND gate (74XX08 or better 74XX244). Just make TFT Tx output more power, which it has not.