Freescale Semiconductor MC9S12XDP512 Microscope & Magnifier User Manual


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Chapter 22 External Bus Interface (S12XEBIV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
868 Freescale Semiconductor
22.4 Functional Description
This section describes the functions of the external bus interface. The availability of external signals and
functions in relation to the operating mode is initially summarized and described in more detail in separate
sub-sections.
22.4.1 Operating Modes and External Bus Properties
A summary of the external bus interface functions for each operating mode is shown in Table 22-7.
Table 22-7. Summary of Functions
Properties
(if Enabled)
Single-Chip Modes Expanded Modes
Normal
Single-Chip
Special
Single-Chip
Normal
Expanded
Emulation
Single-Chip
Emulation
Expanded
Special
Test
Timing Properties
PRR access
1
1
Incl. S12X_EBI registers
2 cycles
read internal
write internal
2 cycles
read internal
write internal
2 cycles
read internal
write internal
2 cycles
read external
write int & ext
2 cycles
read external
write int & ext
2 cycles
read internal
write internal
Internal access
visible externally
——
—
1 cycle 1 cycle 1 cycle
External
address access
and
unimplemented area
access
2
2
Refer to S12X_MMC section.
— — Max. of 2 to 9
programmed
cycles
or n cycles of
ext. wait
3
3
If EWAITE = 1, the minimum number of external bus cycles is 3.
1 cycle Max. of 2 to 9
programmed
cycles
or n cycles of
ext. wait
3
1 cycle
Flash area
address access
4
4
Available only if configured appropriately by ROMON and EROMON (refer to S12X_MMC section).
— — — 1 cycle 1 cycle 1 cycle
Signal Properties
Bus signals — — ADDR[22:1]
DATA[15:0]
ADDR[22:20]/A
CC[2:0]
ADDR[19:16]/
IQSTAT[3:0]
ADDR[15:0]/
IVD[15:0]
DATA[15:0]
ADDR[22:20]/A
CC[2:0]
ADDR[19:16]/
IQSTAT[3:0]
ADDR[15:0]/
IVD[15:0]
DATA[15:0]
ADDR[22:0]
DATA[15:0]
Data select signals
(if 16-bit data bus)
——
UDS
LDS
ADDR0
LSTRB
ADDR0
LSTRB
ADDR0
LSTRB
Data direction signals — —
RE
WE
R/
WR/WR/W
External wait
feature
——
EWAIT — EWAIT —
Reduced input
threshold enabled on
— — Refer to
Table 22-3
DATA[15:0]
EWAIT
DATA[15:0]
EWAIT
Refer to
Table 22-3
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