MB86831 FUJITSU [Fujitsu Component Limited.], MB86831 Datasheet - Page 11

• Manufacturer Part Number: MB86831
• Description: 32-bit Embedded Controller
• Manufacturer: FUJITSU [Fujitsu Component Limited.]

(Continued)
D<31:0>
AS#
RDWR#
BE0#
BE1#
BE2#
BE3#
Symbol
DATA BUS
ADDRESS
STROBE
READ/WRITE
BUS
TRANSACTION
BYTE ENABLE
Pin name
I/O
I/O
I/O
I/O
I/O
O
O
O
Data bus signal.
This pin provides a bidirectional data bus used for instruction fetch,
data load, and data store operations. Instructions and word data must
be aligned at addresses which are multiples of the number 4.
Half words and double words must be aligned at addresses which are
multiples of the numbers 2 and 8, respectively. D<7:0> and D<15:0>
are used in the 8-bit and 16-bit bus modes, respectively. For use in the
16-bit bus mode, a pull-up resistor must be connected to the data bus
which is not used (D<31:8> for the 8-bit bus and D<31:16> for the 16-
bit bus).
Address strobe signal.
This pin outputs the “L” level signal for the first bus cycle. Basically, the
bus cycle starts with the AS# signal asserted and ends up with the
READY# or RDYOUT# signal asserted.
In the bus grant state, the pin serves as an input used for the signals to
actuate the CS generator and wait state generator circuits.
Read/write signal.
This pin outputs the “L” level signal when the current bus cycle is the
write cycle or the “H” level signal when it is the read or idle cycle. The
output level remains at “H” or“L” during the entire bus cycle from the be-
ginning to end.
In the bus grant state, the pin serves as an input used for generating
the DWE0#-DWE3# and DOE# signals to enable the DRAM controller.
The signal at this pin is not used when the DRAM controller is disabled.
Bye enable signals.
These pins are used to indicate the bytes valid for in write mode when
the 32-bit bus width is used.
In read mode, all of the BE0# to BE3# signals are asserted regardless
of the data type. For the 8-bit or 16-bit bus width, the BE2# and BE3#
pins output ADR<1> and ADR<0>, respectively.
The BE0# to BE3# pins remain enabled during the bus cycle; the out-
put level during the idle cycle is not guaranteed.
In the bus grant state, the pins enter the High-Z state and, only when
the DRAM controller is on with the 16-bit bus width used, the BE2# pin
serves as the ADR<1> input pin.
Width of
32-bits
bus
Width of
bus
Write
Read
Half word-0(D<31:16>)
Half word-1(D<15:0>)
Access type
Byte-0 (D<31:24>) *
Byte-1 (D<23:16>)
Byte-2 (D<15:8>)
Byte-3 (D<7:0>)
All data types
Word
Function
MB86830 Series
BE0#
0
1
1
1
0
1
0
0
BE1#
1
0
1
1
0
1
0
0
BE2#
(Continued)
1
1
0
1
1
0
0
0
(Continued)
BE3#
1
1
0
1
0
0
0
1
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