50
Chapter 2
Pin Functions
Preliminary User’s Manual U17566EE1V2UM00
2.2.5
Alternative input selection
Alternative input functions of CSIB0, UART0, UART1, I
2
C0 and I
2
C1 are
provided on two pins each. Thus you can select on which pin the alternative
function should appear. For this purpose, four peripheral function select
registers PFSRk (k = 0, 3) are provided.
Note
The selection of the alternative
input
function is done by a different circuit than
the selection of the alternative
output
function. Therefore, the registers for
selecting the alternative input functions (PFSR) are not reflected in the block
diagrams of the port types in chapter
“Port Types Diagrams“ on page 52
.
(1)
PFSR0 - Peripheral function select register
The 8-bit PFSR0 register selects the alternative input paths for the peripheral
functions CSIB0, I
2
C0 and I
2
C1.
Access
This register can be read/written in 8-bit units.
Address
FFFF F720
H
Initial Value
01
H
. This register is initialized by any reset.
7
6
5
4
3
2
1
0
0
a
a)
These bits must not be changed!
0
a
PFSR05 PFSR04
0
a
0
a
0
a
PFSR00
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Table 2-16
PFSR0 register contents
Bit position
Bit name
Function
5
PFSR05
Specifies the alternative input path for I
2
C1:
0: SCL1 is input from P21 (SCL1_0)
SDA1 is input from P20 (SDA1_0)
1: SCL1 is input from P31 (SCL1_1)
SDA1 is input from P30 (SDA1_1)
4
PFSR04
Specifies the alternative input path for I
2
C0:
0: SCL0 is input from P17 (SCL0_0)
SDA0 is input from P16 (SDA0_0)
1: SCL0 is input from P64 (SCL0_1)
SDA0 is input from P65 (SDA0_1)
0
PFSR00
Specifies the alternative input path for CSIB0:
0: SCKB0 is input from P42 (SCKB0_0)
SIB0 is input from P40 (SIB0_0)
1: SCKB0 is input from P107 (SCKB0_1)
SIB0 is input from P105 (SIB0_1)
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