berni_:
I will check the latest adafruit library for faster operation. Nice example casemod!I have seen on ATMEGA2560 / 1280 data sheet, it has an external memory interface:
ATMEGA1280 pin connections to SRAM device:
Port A = Multiplexed Address low byte (A0....A7) / Data (D0....D7) <--------> Direct connection to SRAM (D0...D7) and connected to Input D of octal latch (typically “74 x 573” or equivalent) to (A0.....A7) of SRAM chip
Port C = Address high byte (A8....A15) <--------> direct connection to for example SRM (A8....A15)
Port G Pin 0 = WR (Write strobe to external memory) <--------> direct connection to for example SRAM WR
Port G Pin 1 = RD (Read strobe to external memory) <--------> direct connection to for example SRAM RD
Port G Pin 2 = ALE (Address Latch Enable to external memory) <--------> Connected to G Input of octal latch (typically “74 x 573” like 74 x 573)Using the hardware pins dedicated to communicat to external memory should make the software several times faster, as fast as using internal RAM. If I have time, I will make a try.
Not quite sure what you're talking about.
Performance is limited by the actual core speed, not the memory itself.
Both the Mega and the UNO are just slow, with the mega having more pins. Technically you can make the LCD on the mega a bit faster by using 16 bit interface, but just a bit.
To unlock the potential of such LCD's you need to use an arduino due or other arm device like a stm32 or a mbed compatible device. In fact with the due you can even crank an SPI display way above the 8MHz limit an uno/mega can drive it.
But if you just want to replace a HD44780 LCD and can live with monochrome graphics on this displays a £3 arduino mini can take care of driving the display quite reasonably. Its just a lot of work writing the code