pca9555bs NXP Semiconductors, pca9555bs Datasheet - Page 7

• Manufacturer Part Number: pca9555bs
• Description: 16-bit I2c And Smbus I/o Port With Interrupt
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9555_7
Product data sheet
6.2.2 Registers 0 and 1: Input port registers
6.2.3 Registers 2 and 3: Output port registers
6.2.4 Registers 4 and 5: Polarity Inversion registers
This register is an input-only port. It reflects the incoming logic levels of the pins,
regardless of whether the pin is defined as an input or an output by Register 3. Writes to
this register have no effect.
The default value ‘X’ is determined by the externally applied logic level.
Table 5.
Table 6.
This register is an output-only port. It reflects the outgoing logic levels of the pins defined
as outputs by Registers 6 and 7. Bit values in this register have no effect on pins defined
as inputs. In turn, reads from this register reflect the value that is in the flip-flop controlling
the output selection, not the actual pin value.
Table 7.
Table 8.
This register allows the user to invert the polarity of the Input port register data. If a bit in
this register is set (written with ‘1’), the Input port data polarity is inverted. If a bit in this
register is cleared (written with a ‘0’), the Input port data polarity is retained.
Table 9.
Table 10.
Bit
Symbol
Default
Bit
Symbol
Default
Bit
Symbol
Default
Bit
Symbol
Default
Bit
Symbol
Default
Bit
Symbol
Default
Input port 0 Register
Input port 1 register
Output port 0 register
Output port 1 register
Polarity Inversion port 0 register
Polarity Inversion port 1 register
O0.7
O1.7
N0.7
N1.7
I0.7
I1.7
X
X
7
7
7
1
7
1
7
0
7
0
O0.6
O1.6
N0.6
N1.6
I0.6
I1.6
Rev. 07 — 5 June 2007
X
X
6
6
6
1
6
1
6
0
6
0
O0.5
O1.5
N0.5
N1.5
I0.5
I1.5
X
X
5
5
5
1
5
1
5
0
5
0
16-bit I
O0.4
O1.4
N0.4
N1.4
I0.4
I1.4
X
X
4
4
4
1
4
1
4
0
4
0
2
C-bus and SMBus I/O port with interrupt
O0.3
O1.3
N0.3
N1.3
I0.3
I1.3
X
X
3
3
3
1
3
1
3
0
3
0
O0.2
O1.2
N0.2
N1.2
I0.2
I1.2
2
X
2
X
2
2
2
2
1
1
0
0
PCA9555
© NXP B.V. 2007. All rights reserved.
O0.1
O1.1
N0.1
N1.1
I0.1
I1.1
X
X
1
1
1
1
1
1
1
0
1
0
O0.0
O1.0
N0.0
N1.0
I0.0
I1.0
X
X
0
0
0
1
0
1
0
0
0
0
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