mc68hc912dg128 Freescale Semiconductor, Inc, mc68hc912dg128 Datasheet - Page 393

• Manufacturer Part Number: mc68hc912dg128
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

MC68HC912DG128 — Rev 3.0
MOTOROLA
Use of an external circuit to condition V
shows a simple circuit that maintains required voltages and filters
transients. V
programming voltage via diode reverse-biases D2, protecting V
excessive reverse current. D2 also protects the FLASH from damage
should programming voltage go to 0. Programming power supply
voltage must be adjusted to compensate for the forward-bias drop
across D1. The charge time constant of R1 and C1 filters transients,
while R2 provides a discharge bleed path to C1. Allow for RC charge and
discharge time constants when applying and removing power. When
using this circuit, keep leakage from external devices connected to the
V
FP
Freescale Semiconductor, Inc.
pin low, to minimize diode voltage drop.
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Go to: www.freescale.com
FP
Electrical Specifications
is pulled to V
Figure 19-1. V
V
DD
4.5V
DD
PROGRAMMING VOLTAGE
22k
FP
via Schottky diode D2. Application of
D2
R2
POWER SUPPLY
Conditioning Circuit
FP
D1
R1
10
C1
0.1 F
is recommended.
V
PIN
FP
Electrical Specifications
Technical Data
Tables of Data
Figure 19-1
DD
from
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