Bus Access In Big-Endian Mode - Fujitsu MB91150 Series Hardware Manual

CHAPTER 4 BUS INTERFACE
4.4.2

Bus Access in Big-endian Mode

Areas not specified in the LER are accessed through an external bus as a big-endian
area.
The FR series ordinarily uses big-endian access.
I Data format
The following figures show the relationship between internal registers and the external bus.
❍ Word access (when an LD or ST instruction is executed)
Figure 4.4-2 Relationship between internal register and external data bus for word access
❍ Half word access (when an LDUH or STH instruction is executed)
Figure 4.4-3 Relationship between internal register and external data for half word access
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Internal register External bus
D31
AA AA
D23
BB BB
D15
CC
D07
DD
Internal register External bus
D31
AA
D23
BB
D15
AA
D07
BB
D31
CC
D23
DD
D31
D23