
Appendix E ROM Description
MC9S12HZ256 Data Sheet, Rev. 2.05
662
Freescale Semiconductor
Appendix E
ROM Description
E.1
Memory Map and Register Denition
ROM control registers are located in the same place as the 16-byte memory space for Flash control
registers 0x0100-0x010F. There are no EEPROM control registers in a ROM device and register locations
0x0110-0x011F are reserved.
E.1.1
ROM Options Register (ROPT)
Upon reset the contents of the non-volatile location NVOPT are copied from ROM into ROPT. This
register may be read at any time, but writes have no meaning or effect.
Table E-1. ROM Memory Map
Address
Use
Access
0x0100
Reserved
Read
0x0101
ROM Options Register (ROPT)
Read
0x0102
Reserved
Read
0x0103
ROM Conguration Register (RCNFG)
Read/Write
0x0104-
0x010B
Reserved
Read
0x010C
Device SC number byte0 (DSC0)
Read
0x010D
Device SC number byte1 (DSC1)
Read
0x010E
Device SC number byte2 (DSC2)
Read
0x010F
Reserved
Read
7
6543210
R
KEYEN1
KEYEN0
NV5
NV4
NV3
NV2
SEC1
SEC0
W
Reset
R
RRRRRRR
= Unimplemented or Reserved
R = Read from ROM
Figure E-1. ROM Options Register (ROPT)