68HC705B5 to 68HC705B16 Conversion

Pay close attention to the following seven differences:

     Memory Map

     1. On the 705B5 User EPROM is $0100-$01FF and $0800-$1EFF
 
        On the 705B16 User EPROM is $0300-$3DFE.
 
 
     2. On the 705B5 the User vectors begin at $1FF2
 
        On the 705B16 the User Vectors begin at $3FF2
 
 
     3. On the 705B5 the Option Register is at address $1EFE.
 
          Address bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
          $1EFE   -    EPP   0   RTIM RWAT WWAT PBPD PCPD
 
        On the 705B16 the Mask Option Register at address $3FDE
 
          Address bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
          $3DFE  -    -    -    RTIM RWAT WWAT PBPD PCPD
 
 
     Errata
 
     4. On the 705B16 the device must be reset a second time after power-on.
        This issue is not present on the 705B5.
 
        The easiest way to power-up a second time is to use the COP.   Below is
        an example of how it is overcome with software.
 
               ORG $0300      Start of User code
 
        START  NOP            Example instructions
               NOP
               NOP
               NOP
               BRA  START
 
        RESET2 BSET 0,$000C   On power-up, the 705B16 first has to
               STOP           service a spurious interrupt. The vector
                              that addresses this interrupt is at address
                              $3FF0. After servicing, we then need
                              another RESET to power-up the device
                              correctly. This is done most simply by
                              initiating a COP reset. Address $000C is
                              the Miscellaneous Register and Bit 0 of
                              this is Watchdog Enable. After this
                              true RESET, this bit is cleared again, if
                              there has been no mask option to enable
                              it. Therefore if the customer is not using
                              the COP in their code, they do not need
                              to worry because it is disabled. If they do
                              want to use the COP in their code, they
                              must enable it again after the true
                              RESET in the way described in the
                              data book.
 
        INT   RTI
 
              ORG   $3FF0     Servicing all other interrupts apart form
 
              FDB   RESET2    Spurious Interrupt Vector
              FDB   INT       SCI  Vector
              FDB   INT       Timer Overflow Vector
              FDB   INT       Timer Output Compare Vector
              FDB   INT       Timer Input Capture Vector
              FDB   INT       External IRQ Vector
              FDB   INT       Software Interrupt Vector
              FDB   START     RESET Vector


 
     Bootloader Options, Programming and Package
 
 
     5. On the 705B16, the bootloader option "EPROM Parallel
        Bootstrap Load" is not available.
 
 
     6. If programming the 705B16 serially, the program to use is
        EPB16.EXE
 
 
     7. On the 705B16 there is no SDIP package available. Connections for
        52 -PLCC
 
              NC - Not connected
              NU - Non-User (should be tied to VSS in an electrically
                   noisy environment)
            VPP1 - Should be left unconnected
            VPP6 - Should be tied to at least VDD
 
            52-PLCC
 
            Device   Pin6  Pin15  Pin40
            ---------------------------
            705B5    NC    VPP6   NU
            705B16   NU    VPP6   VPP1