pca9558pw NXP Semiconductors, pca9558pw Datasheet - Page 6

• Manufacturer Part Number: pca9558pw
• Description: 8-bit I2c And Smbus I/o Port With 5-bit Multiplexed/1-bit Latched 6-bit I2c Eeprom And 2 K Bit Eeprom
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The Multiplexer function controls the six open drain outputs, MUX_OUTx and NON_MUXED_OUT. This control is effected by the input pins
MUX_SELECT (Pin 19), MUX_OUT_LOW (Pin 26), and/or an internal register programmed via the I
function is controlled by the MUX_SELECT and MUX_OUT_LOW pins. When the MUX_SELECT signal is a logic 0, the multiplexer will select
the data from the 6-bit EEPROM to drive on the MUX_OUTx and NON_MUXED_OUT pins. When the MUX_SELECT signal is a logic 1, the
multiplexer will select the MUX_INx pins to drive on the MUX_OUTx pins. The NON_MUXED_OUT output is latched from the 6-bit EEPROM on
a rising edge of the MUX_SELECT signal. This latch is transparent while the MUX_SELECT signal is a logic 0. An internal control register,
written via the I
external pin to an internal register. In this register a bit will act in a similar fashion to the MUX_SELECT input, i.e., a logic 1 will cause the
multiplexer to select data from the 6-bit EEPROM to drive on the MUX_OUTx and NON_MUXED_OUT pins. In this configuration, the
NON_MUXED_OUT will latch data when the PCA9558 acknowledges the I
MUX_OUTx or NON_MUXED_OUT while in this mode. When the MUX_OUT_LOW signal is a logic 0 and the multiplexer is configured so that
the MUX_OUTx pins are being driven by the 6-bit EEPROM, the MUX_OUTx pins will be driven to a logic 0. This information is summarized in
Table 2.
Table 2. Multiplexer function table
NOTES:
1. NON_MUXED_OUT value will be the value present in the 6-bit EEPROM at the time of the rising edge of the MUX_SELECT input.
2. NON_MUXED_OUT value will be the value present int he 6-bit EEPROM at the time of the slave ACK when bit 1 has changed from ‘0’ to ‘1’.
3. These are the 2 LSBs of the MUXCNTRL (Mux Control) Register
If the MUX_OUTx outputs are being driven by the 6-bit EEPROM and this EEPROM is programmed, the outputs will remain stable and change
to the new values after the EEPROM program cycle completes.
Examples of Read/Write for MUX control can be found in Figure 7.
2003 Jun 27
8-bit I
latched 6-bit I
B1
x
x
x
x
0
1
0
1
3
REG.
2
S
B0
C and SMBus I/O port with 5-bit multiplexed/1-bit
2
0
0
0
0
1
1
1
1
1
C-bus, can also control the multiplexer function. When this register is written, the MUX_SELECT function can change from the
3
SLAVE ADDRESS
0
0
MUX_OUT_LOW
1
2
S
1
C EEPROM DIP switch and 2-kbit EEPROM
1
0
0
1
1
0
0
1
1
SLAVE ADDRESS
1 A0 0
0
ACKNOWLEDGE
0
FROM SLAVE
R/W
1
INPUT
A
1
0
1 A0 0
MUX_SELECT
0
COMMAND BYTE
ACKNOWLEDGE
Figure 7. I
Figure 8. I
FROM SLAVE
0
R/W
0
1
0
1
0
x
x
x
x
A
1
0
0
0
2
2
C write for MUXCNTRL register
C read for MUXCNTRL register
COMMAND BYTE
1
ACKNOWLEDGE
0
FROM SLAVE
1
0
A
1
S
6
0
1
2
1
MUX_INx inputs
MUX_INx inputs
MUX_INx inputs
MUX_INx inputs
ACKNOWLEDGE
C-bus. The MUX_SELECT pin will have no effect on the
from EEPROM
from EEPROM
SLAVE ADDRESS
FROM SLAVE
0
MUX_OUTx
1
0
A
0
0
1
0
1
0
1 A0 1
0
DATA BYTE
ACKNOWLEDGE
0
FROM SLAVE
R/W
0
A
0 B1 B0 A
OUTPUT
2
0
C-bus. Upon power-up the multiplex
ACKNOWLEDGE
FROM SLAVE
0
DATA FROM SLAVE
0
latched from EEPROM
latched from EEPROM
latched from EEPROM
latched from EEPROM
0
NON_MUXED_OUT
P
0
from EEPROM
from EEPROM
0 B1 B0 NA
NO ACKNOWLEDGE
FROM MASTER
0
0
PCA9558
SW00636
P
Product data
SW00635
1
1
2
2