Supporting In-Circuit Debugging and Programming Requirements in = Freescale 8-bit MCUs It's AN2497 but there are numerous other related app notes there too. They say: Freescale=92s application note =93HCS08/RS08 Background Debug Mode versus = HC08 Monitor Mode=94 will help you better understand the in-circuit = debugging and programming features of our 8-bit microcontrollers. To = support in-circuit debugging and programming requirements, the = Freescale HC08 family has the monitor mode and the HCS08 and RS08 = utilize a background debug mode (BDM). All three families are = discussed in the application note, which describes: The differences between the HC08 monitor mode and the HCS08 and RS08 = BDM The new background debug controller (BDC) feature available in the = HCS08 and RS08 families The differences between the S08 and RS08 BDM interfaces http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=3D0162= 4684494440&tid=3Dt8nlAN2497 -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist