Philips Semiconductors
Objective specification
SC28L202
Dual UART
2000 Feb 10
39
I/OPCR 0 – I/O Port Configuration Register
Bits 7:6
I/O3 A control
00 = GPI / TxC A
01 = OPR[3] A
10 = TxC A (16X) Output
11 = Reserved
Bits 5:4
I/O2 A control
00 = GPI / CT 0 Clock Input
01 = OPR[2] A / DTRN A
10 = TxC A (1X) Output
11 = Reserved
Bits 3:2
I/O1 A control
00 = GPI / CTSN B
01 = OPR[1] A
10 –
11 = Reserved
Bits 1:0
I/O0 A control
00 = GPI / CTSN A
01 = OPR[0] A
10 –
11 = Reserved
I/OPCR 1 – I/O Port Configuration Register
Bits 7:6
I/O7 A control
00 = GPI / CT 1 Clock Input
01 = OPR[7] A / DTRN B
10 = TxC B (1X) Output
11 = Reserved
Bits 5:4
I/O6 A control
00 = GPI / RxC B / PBRG 1 Clk Input
01 = OPR[6] A
10 = RxC B (16X) Output
11 = Reserved
Bits 3:2
I/O5 A control
00 = GPI / TxC B
01 = OPR[5] A
10 = TxC B (16X) Output
11 = Reserved
Bits 1:0
I/O4 A control
00 = GPI / RxC A / PBRG 0 Clk Input
01 = OPR[4] A
10 = RxC A (16X) Output
11 = Reserved
I/OPCR 2 – I/O Port Configuration Register
Bits 7:6
I/O3 B control
00 = GPI /DSRN B
01 = OPR[3] B
10 = RxC B (1X) Output
11 = C/T 0 Output (open
drain)
Bits 5:4
I/O2 B control
00 = GPI /DSRN A
01 = OPR[2] B
10 = RxC A (1X) Output
11 = C/T 1 Output (open drain)
Bits 3:2
I/O1 B control
00 = GPI
01 = OPR[1] B / RTSN B
10 = Reserved
11 = Reserved
Bits 1:0
I/O0 B control
00 = GPI
01 = OPR[0] B / RTSN B
10 = Reserved
11 = Reserved
I/OPCR 3 – I/O Port Configuration Register
Bits 7:6
I/O7 B control
00 = GPI /RIN B
01 = OPR[7] B
10 =TxINTN B (open drain)
11 =reserved
Bits 5:4
I/O6 B control
00 = GPI /RIN A
01 = OPR[6] B
10 =TxINTN A (open drain)
11 = reserved
Bits 3:2
I/O5 B control
00 = GPI /DCDN B
01 = OPR[5] B
10 = RxINTN B (open
drain)
11 = reserved
Bits 1:0
I/O4 B control
00 = GPI /DCDN A
01 = OPR[4] B
10 = RxINTN A (open drain)
11 = reversed
NOTE
: Both I/O Port A and B default to input upon a hardware reset to avoid hardware conflicts with I/O direction
The four registers above contain 4, 2 bit fields that set the direction and source for each of the I/O pins associated with the channel. The I/O0 B
or I/O1 B output may be RTSN if MR1[7] is set. It may also signal ”end of transmission” if MR2[5] is set. (Please see the descriptions of these
functions under the MR1 and MR2 register descriptions).
The binary settings of the binary 00 combination always configures the I/O pins as “inputs”. However the input circuit of the I/O pins are
ALWAYS active. In actuality the binary 00 condition only disable the output driver of the pin. Since the input circuit and the associated change of
state detector is always active the output signal may generate interrupts or drive counters.
This register resets to 0x00 on reset, effectively configuring all I/O pins as inputs. Inputs may be used as RxC, TxC inputs or CTSN and General
Purpose Inputs simultaneously. All inputs are equipped with change detectors that may be used to generate interrupts or can be polled, as
required.
SOPR A and SOPR B – Set the Output Port Bits (OPR A and OPR B)
SOPR [7:0] – Ones in the byte written to this register will cause the corresponding bit positions in the OPR to set to 1. Zeros have no effect. This
allows software to set individual bits with our keeping a copy of the OPR bit configuration. One register for each channel.
Bit 7
BIT 6
BIT 5
BIT 4
Set OPR Bits
OPR 7
OPR 6
OPR 5
OPR 4
1=set bit
0=no
change
change
change
BIT 3
OPR 3
1=set bit
0=no change
BIT 2
OPR 2
1=set bit
0=no change
BIT 1
OPR 1
1=set bit
0=no change
BIT 0
OPR 0
1=set bit
0=no
change
1=set bit
0=no
1=set bit
0=no
1=set bit
0=no change