The PWM timer block that you see up on top is an optional connection. These TFT-LCDs for reason of cost or footprint will not integrate a timing controller, which means that you buy the TFT module as well as a separate timing ASIC to go along with it, which is added cost into the system. In these cases where the TFT module does not support the timing controller directly, the Blackfin can supply these signals through some extra timers. It would be on the order of what you see here, a signal to start sampling, a signal to denote the scan direction and maybe a clock for gate drivers.