78M6612 Maxim, 78M6612 Datasheet - Page 25

• Manufacturer Part Number: 78M6612
• Description: The Teridian™ 78M6612 is a highly integrated, single-phase, power and energy measurement and monitoring system-on-chip (SoC) that includes a 32-bit compute engine (CE), an MPU core, RTC, and flash
• Manufacturer: Maxim

DS_6612_001
3.9 UART1 (TX1/RX1)
The TX1 and RX1 pins can be used for a regular serial interface (by connecting a RS-232 transceiver for
example), or they can be used to directly operate optical components (for example, an infrared diode and
phototransistor implementing a FLAG interface).
3.10 Connecting V1 and Reset Pins
A voltage divider should be used to establish that V1 is in a safe range (see
lower than 2.9 V in all cases in order to keep the hardware watchdog timer enabled. A series 5 kΩ
resistor (R3) and a capacitor to ground (C1) are added for enhanced EMC immunity. The parallel
impedance of R1 and R2 should be approximately 8 kΩ to 10 kΩ in order to provide hysteresis for the
power fault monitor.
Even though a functional power and measurement unit will not necessarily need a reset switch, it is useful to
have a reset pushbutton switch for prototyping, as shown in
sourced from V3P3SYS, or VBAT (if a battery is present), or from a combination of these sources, depending
on the application.
For production, the RESET pin should be protected by the external components shown in
side. R
can also be directly connected to ground.
Rev 2
Figure 16: External Components for RESET: Development Circuit (Left), Production Circuit (Right)
V3P3D
VBAT/
1
should be in the range of 100 Ω and mounted as closely as possible to the IC. The RESET pin
1k Ω
1k Ω
R
R
2
2
1nF
1nF
Switc
Switc
h
h
Reset
Reset
GND
GND
V3P3
V3P3
Figure 15: Voltage Divider for V1
R
R
10k Ω
10k Ω
V3P3D
1
1
R
R
1
1
R
R
2
2
RESE
T
DGN
DGN
D
D
78M6612
5kΩ
5kΩ
R
R
Figure
3
3
100pF
100pF
C
C
1
1
16, left side. The RESET signal may be
R
R
100
100 Ω
1
1
Figure
V1
V1
15). V1 must be
78M6612 Data Sheet
RESET
DGND
78M6612
Figure
16, right
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