CHAPTER 4 HOW TO USE MINICUBE2 WITH 78K0 MICROCONTROLLER
User’s Manual U18371EJ1V0UM
65
(1) Automatically switching the reset signal via resistor
Figure 4-10 illustrates the reset pin connection described in
4.1.2 Circuit connection examples
.
This connection is designed assuming that the reset circuit on the target system contains an N-ch open-drain
buffer (output resistance: 100
Ω
or less). The VDD or GND level may be unstable when the logic of
RESET_IN/OUT of MINICUBE2 is inverted, so observe the conditions described below in
Remark
.
Figure 4-12. Circuit Connection with Reset Circuit That Contains Buffer
_RESET
MINICUBE2
RESET_OUT
RESET_IN
R1
Reset connector
Buffer
Target device
V
DD
V
DD
R2
_RESET
MINICUBE2
RESET_OUT
RESET_IN
R1
Reset connector
Buffer
Target device
V
DD
V
DD
R2
Remark
Make the resistance of at least R1 ten times that of R2, R1 being 10 k
Ω
or more.
Pull-up resistor R2 is not required if the buffer of the reset circuit consists of CMOS output.
The circuit enclosed by a dashed line is not required when only flash programming is performed.
Figure 4-11 illustrates the circuit connection for the case where the reset circuit on the target system contains
no buffers and the reset signal is only generated via resistors or capacitors. Design the circuit, observing the
conditions described below in
Remark
.
Figure 4-13. Circuit Connection with Reset Circuit That Contains No Buffers
_RESET
MINICUBE2
RESET_OUT
RESET_IN
R1
Reset connector
Target device
R2
V
DD
_RESET
MINICUBE2
RESET_OUT
RESET_IN
R1
Reset connector
Target device
R2
V
DD
Remark
Make the resistance of at least R1 ten times that of R2, R1 being 10 k
Ω
or more.
The circuit enclosed by a dashed line is not required when only flash programming is performed.
