
Chapter 21 Memory Mapping Control (S12XMMCV2)
MC9S12XDP512 Data Sheet, Rev. 2.12
Freescale Semiconductor
827
Due to internal visibility of CPU accesses the CPU will be halted during XGATE or BDM access to any
PRR. This rule applies also in normal modes to ensure that operation of the device is the same as in
emulation modes.
A summary of PRR accesses is the following:
An aligned word access to a PRR will take 2 bus cycles.
A misaligned word access to a PRRs will take 4 cycles. If one of the two bytes accessed by the
misaligned word access is not a PRR, the access will take only 3 cycles.
A byte access to a PRR will take 2 cycles.
Table 21-23. PRR Listing
PRR Name
PRR Local Address
PRR Location
PORTA
$0000
PIM
PORTB
$0001
PIM
DDRA
$0002
PIM
DDRB
$0003
PIM
PORTC
$0004
PIM
PORTD
$0005
PIM
DDRC
$0006
PIM
DDRD
$0007
PIM
PORTE
$0008
PIM
DDRE
$0009
PIM
MMCCTL0
$000A
MMC
MODE
$000B
MMC
PUCR
$000C
PIM
RDRIV
$000D
PIM
EBICTL0
$000E
EBI
EBICTL1
$000F
EBI
Reserved
$0012
MMC
MMCCTL1
$0013
MMC
ECLKCTL
$001C
PIM
Reserved
$001D
PIM
PORTK
$0032
PIM
DDRK
$0033
PIM