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Nitron LCD Terminal

MON08 Programming and Debugging circuits

Nitron Oszillator trimming

AB32 Board

HC08 Flash programming

HCS08 Controller

HCS12 Controller

HC12 Welcome Kit

TBDML HCS12 BDM Tool

Zwobots Display

 

 

 

Microcontroller

   




With a Nitrom 68HC908QY4 and a Hitachi LM052L LC Display I built a little terminal.
The terminal is equipped with a RS232 connector and a debug port, that works with the Motorola User Monitor. I didnīt solderd a level shifter on the board, because I use my little pod, on the controller page or use it directly on a controller. Because the terminal only has to receive characters, I wrote a littele interrupt driven RS232 receive routine. I utilize the KBD interrupt on PTA0 and call the GetbBte ROM routine to receive the character.
The ISR looks like this.

KbdIsr:

pshh                   ;save H-reg
sei                    ;Disable Interrupts
mov  #%00000010,KBIER  ;disable KB-Int
bclr PTA0,PTA          ;initialize PTA0 for serial comms
jsr GetByte            ;call GetByte at adress $2D6b
sta data               ;store the received character in RAM
mov #%00000100,KBSCR   ;Clear Pending KBD interrupts
mov #%00000001,KBIER   ;enable Keyboard interrupts
cli                    ;enable ints
pulh                   ;get H-reg back
rti

You can find schematics here. lcdschem.gif The software is here lcdterme.asm. It would fit into the 1.5 kB Flash of the 68HC908QY1 or 68HC908QY2 too, but I had the 4 kB Version lying around so I used them.
Another display project is Zwobots Display. This project is programmed n C and uses a hardware SCI.

 

 

 

 
     

 

   © 2005 by Eckhard Gosch •  eckhard@eckhard-gosch.de