Freescale Semiconductor Microcontrollers - Manual (Page 609)

ColdFire V1 Full Chip Simulation Connection
FCS Visualization Utilities
609 Microcontrollers Debugger Manual
Figure 28.32 The DDRAM Controller
The Address Counter (AC) is an internal register of the display controller which points at
the current address. In the default configuration AC is initialized at 00h and increases
when an ASCII character is stored at the address to which AC points. When AC is equal to
1Fh, the next increased value is not 20h, but 40h.
For example, if we send a 48-character string after initialization, the AC stores the bytes at
addresses 00h to 1Fh and 40h to 4Fh.
NOTE Only characters having their ASCII codes in the visible interval of the 16
characters (positions 1 to 16) of RAM appear.
Sending Information to the Display
Two steps are necessary to display a character:
1. Set the E and RS bits at 1 and the R/W bit at 0 (control word 00000100b)
2. Write the character ASCII code on the data port. Set bit E to 0 (this validates bits d7-
d0).
For an instruction, only step 2 is different: the Byte to write on the data port is the
instruction code you want the display controller to execute.