# ESN Device Address Mapping

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  DEVICE                 PAGE :                           CNT    ACTIVE BUS     BUS CONTROLLER INSTRUCTION
                         ADDRESS                                                               
  ----------------- ---- --------- -------- ---- -------- ------ -------------- -------------- -------------
  **Program "Boot   P:             0:0000   \-   0:7FFF   32K    Instruction.   IntProcesor    Ld/St
  Up" ROM**                                                                                    Instruction

  **Program RAM**   P:             0:8000   \-   0:FFFF   32K    Instruction    Int Processor  Ld/St
                                                                                               Instruction

  **External Inst.  P:             1:0000   \-   F:FFFF   960K   Instruction    IntProcessor   Ld/St
  Memory**                                                                                     Instruction

                                                                                               

  **Data RAM**      M:             0000     \-   7FFF     32K    Operand        Int/Ext Proc   Ld/St Operand

                                                                                               

  **Shared RAM**    M:             8000     \-   FFFF     32K    Oper & Shared  Int/Ext Proc   Ld/St Operand

                    S:             8000     \-   FFFF     32K    Shared         BCRTM          Ld/St Operand
                                   (0000)        (7FFF)                                        

                                                                                               

  **User Defined    I:             0000     \-   FEFF     64K    Operand        Int/Ext Proc   In/Out
  Ext. I/O**                                                                                   Operand

  **Reserved I/O**  I:             FF00     \-   FF7F     128    Operand        Int/Ext Proc   In/Out
                                                                                               Operand

                                                                                               

  **BCRTM           I:             FF80     \-   FF9F     32     Operand        Int/Ext Proc   In/Out
  Registers:**                                                                                 Operand

                                                                                               

  **External Device I:             FFA0     \-   FFAF     16     Operand        Int/Ext Proc   In/Out
  Select #1**                                                                                  Operand

  **External Device I:             FFB0     \-   FFBF     16     Operand        Int/Ext Proc   In/Out
  Select #2**                                                                                  Operand

  **External Device I:             FFC0     \-   FFCF     16     Operand        Int/Ext Proc   In/Out
  Select #3**                                                                                  Operand

  **External Device I:             FFD0     \-   FFDF     16     Operand        Int/Ext Proc   In/Out
  Select #4**                                                                                  Operand

                                                                                               

  **UART #1 (8251A) I:             FFE0                   1      Operand        Int/Ext Proc   In/Out
  Data**                                                                                       Operand

  **UART #1 (8251A) I:             FFE1                   1      Operand        Int/Ext Proc   In/Out
  Control**                                                                                    Operand

  **UART #2 (8251A) I:             FFE2                   1      Operand        Int/Ext Proc   In/Out
  Data**                                                                                       Operand

  **UART #2 (8251A) I:             FFE3                   1      Operand        Int/Ext Proc   In/Out
  Control**                                                                                    Operand

                                                                                               

  **Port Interface  I:             FFE4                   1      Operand        Int/Ext Proc   In/Out
  (8255) Port A**                                                                              Operand

  **Port Interface  I:             FFE5                   1      Operand        Int/Ext Proc   In/Out
  (8255) Port B**                                                                              Operand

  **Port Interface  I:             FFE6                   1      Operand        Int/Ext Proc   In/Out
  (8255) Port C**                                                                              Operand

  **Port Interface  I:             FFE7                   1      Operand        Int/Ext Proc   In/Out
  (8255) Port D**                                                                              Operand

                                                                                               

  **Timer #1 (8254) I:             FFE8                   1      Operand        Int/Ext Proc   In/Out
  Counter 1**                                                                                  Operand

  **Timer #1 (8254) I:             FFE9                   1      Operand        Int/Ext Proc   In/Out
  Counter 2**                                                                                  Operand

  **Timer #1 (8254) I:             FFEA                   1      Operand        Int/Ext Proc   In/Out
  Counter 3**                                                                                  Operand

  **Timer #1 (8254) I:             FFEB                   1      Operand        Int/Ext Proc   In/Out
  Control**                                                                                    Operand

                                                                                               

  **Watch Dog       I:             FFEC                   1      Operand        Int/Ext Proc   In/Out
  Timer**                                                                                      Operand

                                                                                               

  **SST#1 Count     I:             FFEC                   1      Operand        Int/Ext Proc   In/Out
  Register LSW**                                                                               Operand

  **SST#1 Count     I:             FFED                   1      Operand        Int/Ext Proc   In/Out
  Register MSB**                                                                               Operand

  **SST#2 Count     I:             FFEE                   1      Operand        Int/Ext Proc   In/Out
  Register LSW**                                                                               Operand

  **SST#2 Count     I:             FFEF                   1      Operand        Int/Ext Proc   In/Out
  Register MSB**                                                                               Operand

  **SST#2 Count     M:             8000                   1      Operand        Int/Ext Proc   In/Out
  Register Latch**                                                                             Operand

                    S:             0000                   1      Operand        Int/Ext Proc   In/Out
                                                                                               Operand

  **SST#3 Count     I:             FFFE                   1      Operand        Int/Ext Proc   In/Out
  Register LSW**                                                                               Operand

  **SST#3 Count     I:             FFFF                   1      Operand        Int/Ext Proc   In/Out
  Register MSB**                                                                               Operand

  **SST#4 Count     I:             FFE3                   1      Operand        Int/Ext Proc   In/Out
  Register LSW**                                                                               Operand

  **SST#4 Count     I:             FFE7                   1      Operand        Int/Ext Proc   In/Out
  Register MSB**                                                                               Operand

                                                                                               

  **Config. /       I:             FFF4                   1      Operand        Int/Ext Proc   In/Out
  Status Register**                                                                            Operand

  **Wait State Gen. I:             FFF5                   1      Operand        Int/Ext Proc   In/Out
  Register**                                                                                   Operand

  **Sleep Mode      I:             FFF6                   1      Operand        Int/Ext Proc   In/Out
  Register**                                                                                   Operand

                                                                                               

  **Timer #2 (8254) I:             FFF8                   1      Operand        Int/Ext Proc   In/Out
  Counter 1**                                                                                  Operand

  **Timer #2 (8254) I:             FFF9                   1      Operand        Int/Ext Proc   In/Out
  Counter 2**                                                                                  Operand

  **Timer #2 (8254) I:             FFFA                   1      Operand        Int/Ext Proc   In/Out
  Counter 3**                                                                                  Operand

  **Timer #2 (8254) I:             FFFB                   1      Operand        Int/Ext Proc   In/Out
  Control**                                                                                    Operand

                                                                                               

  **S/P & P/S Data  I:             FFFC                   1      Operand        Int/Ext Proc   In/Out
  Register**                                                                                   Operand

  **S/P & P/S       I:             FFFD                   1      Operand        Int/Ext Proc   In/Out
  Control /                                                                                    Operand
  Status**                                                                                     

                                                                                               

  **Processor       S:             FF00     \-   FF1F     32     Shared         BCRTM          Ld/St Operand
  Indep. I/O**                                                                                 

  P: Program Page                                                                              
  (Instr. Bus) M:                                                                              
  Memory Page                                                                                  
  (Oper./Shared                                                                                
  Bus) I: I/O Page                                                                             
  (Oper. Bus) S:                                                                               
  BCRTM Page                                                                                   
  (Shared Bus)                                                                                 
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