Above is a picture of the 64Kb addressing space of an HC11 (note that this is not an exact drawing since it has no other memory but the int. RAM).  Notice that the picture expands addresses $1000 - $103F?  This is where all the internal registers and ports are located.  This expansion does not show the registers, but only the ports of an HC11.  I will quickly talk about the ports, and the direction register (if they have one).  PORTA is located at $1000, PORTB is located at $1004, PORTC is located at $1003 (PORTC is a bi-directional port, so it has a data direction register DDRC [$1007], poking a '1' to bit 0 of DDRC will make PC0 an output while poking a '0' to bit 0 of DDRC will make PC0 an input [bit 1 of DDRC means PC1 etc.]).  PORTD is located at $1008 (the data direction register for PORTD is at $1009 which is used the same way as PORTC).  Now the last port (PORTE), which can serve as a digital input or an analog input( see how to use the ADC), is located at $100A .

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