71m6521be Maxim Integrated Products, Inc., 71m6521be Datasheet - Page 66

• Manufacturer Part Number: 71m6521be
• Description: Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

Capacitors to ground must be used for protection from EMI. Production boards should have the ICE_E pin connected to
ground.
If the ICE pins are used to drive LCD segments, the pull-up resistors should be omitted, as shown in Figure 37, and 22pF
capacitors to GNDD should be used for protection from EMI.
It is important to bring out the ICE_E pin to the programming interface in order to create a way for reprogramming
parts that have the flash SECURE bit (SFR 0xB2[6]) set. Providing access to ICE_E ensures that the part can be reset
between erase and program cycles, which will enable programming devices to reprogram the part. The reset required is im-
plemented with a watchdog timer reset (i.e. the hardware WDT must be enabled).
Page: 66 of 97
V3P3D
V3P3D
VBAT/
VBAT/
Figure 36: External Components for the RESET Pin: Push-Button (Left), EMI Circuit (Right)
1kΩ
1kΩ
R
R
2
2
1nF
1nF
Switch
Switch
Reset
Reset
Figure 37: External Components for the Emulator Interface
62Ω
62Ω
62Ω
62Ω
V3P3D
V3P3D
Connecting the Emulator Port Pins
© 2005-2008 TERIDIAN Semiconductor Corporation
62Ω
62Ω
R
R
V3P3D
V3P3D
10kΩ
10kΩ
1
1
22pF
22pF 22pF
LCD Segments
LCD Segments
22pF
(optional)
(optional)
RESET
RESET
DGND
DGND
71M6521
71M6521
ICE_E
ICE_E
E_RST
E_RST
E_RXTX
E_RXTX
E_TCLK
E_TCLK
71M6521B
71M6521B
R
R
Energy Meter IC
100Ω
100Ω
1
1
71M6521BE
DATA SHEET
RESET
RESET
DGND
DGND
71M6521
71M6521
JANUARY 2008
V1.0