gc80c520a CORERIVER Semiconductor, gc80c520a Datasheet - Page 168

• Manufacturer Part Number: gc80c520a
• Description: Midas1.0 Family Mask Rom/eprom/romless 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

15.16 Serial Data Buffer Register (SBUF)
Data for serial port is read from or written to this location. The serial transmit and receive buffers are
separate registers, but both are addressed at the same location.
15.17 Port 2 Register (P2)
This port functions as an address bus during external memory access, and as a general purpose I/O port
on devices which incorporate internal program memory. During external memory cycles, this port will
contain the MSB of the address.
15.18 Port 4 Register (P4)
This register functions as a general purpose I/O port in the 44-PLCC/44-LQFP package.
15.19 Port 4 Pull-up Control Register (P4SEL)
Bit No.
Bit No.
Bit No.
Bit No.
A0h
A5h
A6h
99h
R/W(0)
R/W(1)
SBUF.7
P2.7
7
-
-
7
7
7
-
-
SM2. In modes 2 and 3, RI is set after the last sample of RB8. This bit must be manually
cleared by software.
SBUF.6
R/W(0)
R/W(1)
6
-
-
P2.6
6
6
6
-
-
5
-
-
SBUF.5
R/W(0)
R/W(1)
P2.5
5
5
5
-
-
4
-
-
SBUF.4
R/W(0)
R/W(1)
Page 168 of 187
P2.4
4
4
4
-
-
P4SEL.3
R/W(0)
3
SBUF.3
R/W(0)
R/W(1)
R/W(1)
P2.3
P4.3
3
3
3
P4SEL.2
R/W(0)
2
R/W(0)
R/W(1)
R/W(1)
SBUF.2
P2.2
P4.2
2
2
2
P4SEL.1
R/W(0)
Appendix B: SFR description
SBUF.1
R/W(0)
R/W(1)
R/W(1)
1
P2.1
P4.1
1
1
1
P4SEL.0
R/W(0)
SBUF.0
R/W(0)
R/W(1)
R/W(1)
P2.0
P4.0
0
0
0
0
P4SEL
SBUF
P2
P4