EM78808
8-bit Micro-controller
IOD0~IOD7
PH1OUT
O
O
I/O data bus.
Phase 1 output
ROMA0..RO
MA19
ROMD0..RO
MD7
ROMEN1..R
OMEN4
O
External data ROM address
External data ROM data bus
IO
O
Data ROM enable pin. User can select one of four external DATA
ROM by these enable signal. Please refer to RB address of data
ROM.
ROMA21,ROMA20
ROMEN4, ROMEN3, ROMEN2,
ROMEN1
1,1,1,0
0 0
0 1
1,1,0,1
1 0
1 1
1,0,1,1
0,1,1,1
ROMREAD
ROMWRITE
O
O
External data ROM reading signal. Normal high . When you read
data ROM, it will generate a low pulse a instruction long.
External data ROM writing signal. Normal high . When you write
data ROM, it will generate a low pulse a instruction long.
VII Operational Registers
R9
PAGE1 (LCD address MSB bit, Data ROM address bits)
7
6
5
4
3
2
1
0
LCDA8
-
DROM_A21 DROM_A20 DROM_A19 DROM_A18 DROM_A17 DROM_A16
Bit 0~Bit 5(DROM_A16~DROM_A21) : Data ROM address(16~21) for ROM reading.
Bit 6 : unused
Bit 7(LCDA8) : MSB of LCD address for LCD RAM reading or writing
Other LCD address bits LCDA7 ~ LCDA0 are set from RA PAGE1 Bit 7 ~ Bit 0.
For LCD address access over 0xFFH, set this bit to “1”; otherwise set this bit to “0”.
IOC5
PAGE2 ( Stack Pointer )
7
6
5
4
3
2
1
0
STKF
STKM
STKP5
STKP4
STKP3
STKP2
STKP1
STKP0
Bit 0~Bt 5(STKP0~STKP5) : Stack Point selection bits( User must enable CODE Option Register bit 2 before
using Stack pointer function )
Stack5 Stack4 STKP3 STKP2 STKP1 STKP0
Stack Point
Stack 0
Stack 1
Stack 2
Stack 3
:
0
0
0
0
0
0
0
0
0
0
0
0
:
:
1
1
0
0
0
0
:
:
1
1
0
0
0
0
:
:
1
1
0
0
1
1
:
:
1
1
0
1
0
1
:
:
0
1
:
Stack 30
Stack 31
______________________________________________________________________________________________________________________________________________________
* This specification is subject to change without notice.
8/1/2004 (V3.1)
61
ELAN [ ELAN MICROELECTRONICS CORP ]
