FDS_6533_6534_004
71M6533/71M6534 Data Sheet
R1
R3
V3P3
GND
16.9kΩ
V1
20kΩ
C1
100pF
R2
Figure 38: Voltage Divider for V1
3.12 Connecting the Reset Pin
Even though a functional meter will not necessarily need a reset switch, it is useful to have a reset push-
button for prototyping as shown in Figure 39, left side. The RESET signal may be sourced from
V3P3SYS (functional in MISSION mode only), V3P3D (MISSION and BROWNOUT modes), or VBAT (all
modes, if a battery is present), or from a combination of these sources, depending on the application.
For a production meter, the RESET pin should be protected by the by the external components shown in
Figure 39, right side. R1 should be in the range of 100Ω and mounted as closely as possible to the IC.
Since the 71M6533 and 71M6534 generates its own power-on reset, a reset button or circuitry, as
shown in Figure 39, is only required for test units and prototypes.
VBAT/
V3P3D
71M6533/
71M6533
71M6533/
71M6534
V3P3D
10k?
R2
71M6534
1k?
Reset
Switch
RESET
RESET
100Ω
R1
DGND
0.1µF
R1
DGND
Figure 39: External Components for the RESET Pin: Push-Button (Left), Production Circuit (Right)
3.13 Connecting the Emulator Port Pins
Even when the emulator is not used, small shunt capacitors to ground (22 pF) should be used for protec-
tion from EMI as illustrated in Figure 40. Production boards should have the ICE_E pin connected to
ground via a resistor of around 200 Ω.
The 71M6534 is capable of supporting a trace emulator. To connect this non-standard emulator, the pins
E_TBUS0 (SEG51) – E_TBUS3 (SEG54) and E_ISYNC (SEG55) have to be brought out to the emulator
interface.
v1.1
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