HT9580 データシートの表示（PDF） - Holtek Semiconductor
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HT9580 Datasheet PDF : 63 Pages
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P A D a ta
Preliminary
V DD
EN
M
U
X
P u ll- u p
R e s is to r
HT9580
PAC
P A IM
To
CPU
O ne
S hot
C ir c u it
PAW UE
I/O structure of port A
Mask ROM (Character ROM) bank point register
Address
Register
Name
Bit 7
Bit 6
0015H MROM-BP BP_MODM1 BP_MODM0
Bit 5
M_BP5
Bit 4
M_BP4
Bit 3
M_BP3
Bit 2
M_BP2
Bit 1
M_BP1
Bit 0
M_BP0
State on
POR
0000 0000
The Mask ROM bank point register can switch
between the internal 2 Mbits Mask ROM or an
external up to 2 Mbits Mask ROM space. The se-
lection table is based on the following table. The
space size of each Mask ROM bank is 8 Kbytes.
The bits BP_MODM1 and BP_MODM0 define
whether internal or external Mask ROM devices
are used. (BP_MODM1, BP_MODM0)=(0, 1), se-
lects the internal Mask ROM device.
(BP_MODM1, BP_MODM0)=(1, 0), selects the
external Mask ROM device. The internal Mask
ROM can switch from bank 0 to bank 31 and the
external Mask ROM can switch from bank 0 to
bnak 31 by software programming. In addition,
the address range of the internal/external Mask
ROM will all range from 1000H to 2FFFH.
The Mask ROM bank point register selection
table is shown in the table.
BP_MODM1 BP_MODM0 M_BP5 M_BP4 M_BP3 M_BP2 M_BP1 M_BP0 BP Value
0
0
X
X
X
X
X
X
X
Reserved
Memory Area
0
1
0
0
0
0
0
0
0
Internal 2 Mbits Mask ROM (low 8 Kbytes)
0
1
¯
¯
¯
0
1
0
1
1
1
1
1
31
Internal 2 Mbits Mask ROM (High 8
Kbytes)
0
1
1
0
0
0
0
0
32 Reserved
0
1
¯
¯
Reserved
0
1
1
1
1
1
1
1
63
Reserved
1
0
0
0
0
0
0
0
0
External 2 Mbits Mask ROM (low 8 Kbytes)
1
0
¯
¯
¯
1
0
0
1
1
1
1
1
31
External 2 Mbits Mask ROM (High 8
Kbytes)
20
April 28, 2000
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