Freescale Semiconductor HCS12X, Reference Manual

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Chapter 5 External Bus Interface (S12XEBIV4)
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor 249
5.4.2 Internal Visibility
Internal visibility allows the observation of the internal CPU address and data bus as well as the
determination of the access source and the CPU pipe (queue) status through the external bus interface.
Internal visibility is always enabled in emulation single chip mode and emulation expanded mode. Internal
CPU accesses are made visible on the external bus interface except CPU execution of BDM firmware
instructions.
Internal reads are made visible on ADDRx/IVDx (address and read data multiplexed, see Table 5-12 to
Table 5-14 ), internal writes on ADDRx and DATAx (see Table 5-15 to Table 5-17 ). RW and LSTRB
show the type of access. External read data are also visible on IVDx.
During ‘no access’ cycles RW is held in read position while LSTRB is undetermined.
All accesses which make use of the external bus interface are considered external accesses.
Flash area
address access
(4)
— — — 1 cycle 1 cycle 1 cycle
Signal Properties
Bus signals — — ADDR[22:1]
DATA[15:0]
ADDR[22:20]/
ACC[2:0]
ADDR[19:16]/
IQSTAT[3:0]
ADDR[15:0]/
IVD[15:0]
DATA[15:0]
ADDR[22:20]/
ACC[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
RW RW RW
Chip Selects — —
CS0
CS1
CS2
CS3
—
CS0
CS1
CS2
CS3
—
External wait
feature
— — EWAIT — EWAIT —
Reduced input
threshold enabled on
— — Refer to
Table 5-4
DATA[15:0]
EWAIT
DATA[15:0]
EWAIT
Refer to
Table 5-4
1. Incl. S12X_EBI registers
2. Refer to S12X_MMC section.
3. If EWAIT enabled for at least one CSx line (refer to S12X_MMC section), the minimum number of external bus cycles is 3.
4. Available only if configured appropriately by ROMON and EROMON (refer to S12X_MMC section).
Table 5-9. Summary of Functions (continued)
Properties
(if Enabled)
Single-Chip Modes Expanded Modes
Normal
Single-Chip
Special
Single-Chip
Normal
Expanded
Emulation
Single-Chip
Emulation
Expanded Special
Test
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages