firmware history

V8: 29.8.2012
  added self captured 16C ROM, now we got them all
  added LCD contrast settings [ON]+[CHS]
  updated annunciators in key-test for 10C

V7: 15.7.2012
  Fixed problem with MEM display on 15C
  added battery voltage displayed in [ON]+[E] screen
  added read battery voltage on console (calculators from first batch do not have a Vref diode)
  
V6: 1.7.2012
  removed the firmware naming 'VANILLA'
  all ROM files are based on own extraction except for the 16C which we don't have yet
  changed CPU speed to 48MHz. switch to 12MHz and back with [ON]+[9]

V4: 4.4.2012
  fixed PREFIX shows the enhanced MEM display

V3: 25.3.2012
  Enhanced MEM display for memory extended firmwares
  [ON]+[E] displays firmware version on LCD

V2: 22.3.2012
  initial release DM11CC
  
V2: 14.3.2012
  initial release DM12CC

V2: 21.2.2012:
  corrected ROM in DM15CC_ROM_MEM80_V2.hex
  thanks to Jean-Francois Garnier for pointing to that mistake 

V1: 10.2.2012:
  initial verions DM15CC, DM16CC