AN_6612_007
78M6612 Hardware Design Guidelines
Rev 2
15
5.8 Connecting 3-Wire EEPROMs
Connect MICROWIRE® EEPROMs and other compatible devices to DIO pins DIO4 and DIO5 as shown
in Figure 13. Connect DIO5 to both the DI and DO pins of the three-wire device. Connect the CS pin to a
vacant 78M6612 DIO pin. Add a pull-up resistor of roughly 10 k
Ω
to V3P3 to the DI/DO signals. Add a
pull-down resistor to the CS pin to prevent that the 3-wire device from being enabled on power-up before
the 78M6612 can establish a stable signal for CS. The I/O RAM register
DIO_EEX
must be set to 10 in
order to convert the DIO pins DIO4 and DIO5 to
µ
Wire operational mode pins.
Figure 14: 3-Wire EEPROM Connection
5.9 UART0 (TX/RX)
Attach a 10 k
Ω
pull-down resistor to the RX input pin. Additionally, include a 100 pF ceramic capacitor for
EMI protection as shown in Figure 14.
Figure 15: Connections for the RX Pin
5.10 UART1 Interface
The TX1 and RX1 (UART1) pins can be used as a regular serial UART interface, e.g. by connecting a
RS-232 transceiver.
Alternatively, they can directly interface to optical components, e.g. an infrared diode and phototransistor
implementing a FLAG interface. Contact Maxim’s Teridian™ applications support for more information at
TX
RX
10k
Ω
100pF
RX
TX
TX
RX
78M6612
10k
Ω
100pF
RX
TX
DIO4
DIO5
EEPROM
SCLK
DI
10k
Ω
CS
DIOn
DO
10k
Ω
DIO4
DIO5
78M6612
EEPROM
SCLK
DI
V3P3
10k
Ω
CS
DIOn
DO
10k
Ω
MICROWIRE is a registered trademark of National Semiconductor Corp.
Teridian is a trademark of Maxim Integrated Products, Inc.
