hessch / udgbuf

UDGFB - Framebuffer using HD44780 User Defined Characters for Psion II

Hessel Schut [e-mail]

(c) 2009,2013 isquared.nl, Licensed under Creative Commons CC BY-SA 3.0

UDGFB is a 20x16 framebuffer for Psion Organiser II devices based on the eight user-defined characters for the Hitachi HD44780 LCD controller in these devices.

The framebuffer uses the user-defined characters printed in the following configuration:

udg0 udg1 udg2 udg3
udg4 udg5 udg6 udg7

See this and this blog posts for more details.

The following functions are defined:

• clearfb:

  clears the framebuffer

• printfb:(xpos, ypos)

  print framebuffer UDGs at location (xpos, ypos)

• pset:(x, y, s)

  set pixel at (x, y) to state s, where "s" is 0 or 1

• pixel%:(x, y)

  get value of pixel at (x, y)

• blitup:

  scroll all pixels one row up, duplicates row 15

The following functions are for internal use:

• pokeudg:(char, row, value)

  write value to udg row of udg character

• peekudg%:(char, row)

  read byte defining row of udg character