71M6511/71M6511H
Single-Phase Energy Meter IC
DATA SHEET
AUGUST 2007
Connecting I2C EEPROMs
I2C EEPROMs or other I2C compatible devices should be connected to the DIO pins DIO4 and DIO5, as shown in Figure 35.
Pull-up resistors of roughly 3kΩ to V3P3 should be used for both SCL and SDA signals. The DIO_EEX register in I/O RAM
must be set to 1 in order to convert the DIO pins DIO4 and DIO5 to I2C pins SCL and SDA.
V3P3
3kΩ
71M6511
3kΩ
EEPROM
DIO4
DIO5
SCL
SDA
Figure 35: EEPROM Connection
Connecting 5V Devices
In general, all pins of the 71M6511 are compatible with external 5V devices. The exceptions are the power supply pins and the
RX pin of the UART (see section Electrical Specifications).
V3P3
71M651X
R1 = 100kΩ
RX
VIN
Figure 36: Interfacing RX to a 0-5V Signal
Figure 36 shows how a 5V signal from an external device can be safely interfaced to the RX pin.
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