78M6612 Data Sheet
DS_6612_001
R1
R3
V3P3
GND
5kΩ
V1
C1
100pF
R2
Figure 36: Voltage Divider for V1
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 Figure 37, left side. The RESET
signal may be sourced from V3P3SYS (functional in MISSION mode only), V3P3D (MISSION and
BROWNOUT modes), VBAT (all modes, if battery is present), or from a combination of these sources,
depending on the application. For a production unit, the RESET pin should be protected by the external
components shown in Figure 37, right side. R1 should be in the range of 100 Ω and mounted as closely
as possible to the IC. The RESET pin can also be directly connected to ground.
Since the 78M6612 generates its own power-on reset, a reset button or circuitry, as shown in
Figure 37, left side, is only required for test units and prototypes.
VBAT/
V3P3
78M6612
78M6612
V3P3
R2
1k Ω
Reset
Switch
RESET
RESET
100 Ω
R1
10k Ω
1nF
R1
DGND
DGND
Figure 37: External Components for RESET: Development Circuit (Left), Production Circuit
(Right)
3.12 Connecting the Emulator Port Pins
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 38, and 22 pF 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 implemented with a watchdog timer
reset (i.e. the hardware WDT must be enabled).
72
Rev. 1.2
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
