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MB90420/5 (A) SERIES F
7.2 Mode Pins (MD2 to MD0)
The mode pins are three external pins (MD2 to MD0), and specify the input type of the reset vectors and
mode data.
n Mode pins (MD2 to MD0)
The mode pins determine whether to read the reset vectors to the external or internal data bus, and select
the bus width when the external data bus is selected. For a FLASH ROM bulit-in product, the mode pins
also specify the FLASH ROM writing mode to write programs to internal ROM. The setting of the mode pins
is shown in Table 7-1.
MD2
MD1
MD0
0
0
0
0
0
1
0
1
0
Internal vector
0
1
1
mode
1
0
0
1
0
1
1
1
0
FLASH writer
1
1
1
writing mode
Set MD2 to MD0: 0 = V
Note:
In the MB90420/5 (A) series, only the single-chip mode is used, so set MD2, MD1, and MD0 to 011,
and set M1 and M0 to 00.
2
MC-16LX FAMILY 16-BIT MICROCONTROLLERS HARDWARE MANUAL
Table 7-1 Setting of Mode Pins
Reset Vector
Mode Name
Access Area
Internal
—
or 1 = V
.
SS
CC
External Data Bus
Width
Setting disabled
Mode data
Setting disabled
—
7-4
Remarks
Operation after reset sequence
is controlled by mode data.
—
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