PCA9561_04 Datasheet, PDF (6/17 Pages) NXP Semiconductors – Quad 6-bit multiplexed I2C EEPROM DIP switch

Philips Semiconductors
Quad 6-bit multiplexed I²C EEPROM DIP switch
Product data sheet
PCA9561
EXTERNAL CONTROL SIGNALS
The Write Protect (WP) input is used to control the ability to write the content of the non-volatile registers. If the WP signal is logic 0, the I²C-bus
will be able to write the contents of the non-volatile registers. If the WP signal is logic 1, data will not be allowed to be written into the
non-volatile registers. In this case, the slave address and the command code will be acknowledged but the following data bytes will not be
acknowledged and the EEPROM is not updated.
The factory default for the contents of the non-volatile register are all logic 0. These stored values can be read or written using the I²C-bus
(described in the next section).
The WP, MUX_IN*, and MUX_SELECT signals have internal pull-up resistors. See the DC and AC Characteristics for hysteresis and signal
spike suppression figures.
Function Table¹
WP
MUX_SELECT
COMMANDS
0
X
Write to the non-volatile registers through I²C-bus allowed
1
X
Write to the non-volatile registers through I²C-bus not allowed
X
0
MUX_OUT from EEPROM byte 0–3
(EEPROM selected through I²C – see Table 2)
X
1
NOTE:
1. This table is valid when not overridden by I²C control register.
MUX_OUT from MUX_IN inputs
POWER-ON RESET (POR)
When power is applied to V_DD, an internal power-on reset holds the PCA9561 in a reset state until V_DD has reached V_POR. At that point, the
reset condition is released and the PCA9561 volatile registers and state machine will initialize to their default states.
The MUX_OUT pin values depend on the MUX_SELECT logic level:
– if MUX_SELECT = 0, the MUX_OUT pin output values will equal the previously stored EEPROM byte 0 values regardless of the last
non-volative EEPROM byte selected by the command byte prior to power down.
– if MUX_SELECT = 1, the MUX_OUT output values will equal the MUX_IN pin input values as shown in the Function Table.
2004 May 17
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