Many of us always wanted to interface a TFT screen to an arduino to make our projects look more beautiful. However most of the TFT modules require a 16-bit data line and are mainly designed to be connected to an ARM based processor. Also majority of the TFT modules run on 3.3V instead of regular 5V and also the 16-bit data bus can take up a lot of GPIO pins of the arduino. Both the problems were solved by combination of hardware and software. In the hardware an on board level converter was implemented along with a latch that would reduce the number of pins form 16 to 8 at the expense of an additional pin for controlling the latch.
The latch works sort of like a small memory. The SN74LV573APW transparent D-Type latch, from Texas Instruments, was used as a latch as it satisfies the speed requirements imposed by the XMEM interface and is easy to find on the market. For the level conversion, the SN54LVTH2245 octal bus transceiver, again from Texas Instruments is an ideal choice for level conversion in this design. The propagation delay at 3.3V is around 2ns which is very fast. The inputs and outputs are on opposite sides of the package which simplifies routing and it’s easy to find the device on the market.