NEC UPD789426 Series User Manual page 299

(1) Signal conflict
A signal conflict occurs if the dedicated flash programmer (output) is connected to a serial interface pin
(input) connected to another device (output). To prevent this signal conflict, isolate the connection with the
other device or put the other device in the output high impedance status.
µ
PD78F9436,
Input pin
(2) Malfunction of another device
When the dedicated flash programmer (output or input) is connected to a serial interface pin (input or output)
connected to another device (input), a signal may be output to the device, causing a malfunction. To prevent
such malfunction, isolate the connection with other device or set so that the input signal to the device is
ignored.
µ
PD78F9436,
78F9456
Pin
µ
PD78F9436,
78F9456
Pin
300
CHAPTER 17
Figure 17-5. Signal Conflict (Serial Interface Input Pin)
78F9456
Signal conflict
In the flash memory programming mode, the signal
output by another device and the signal sent by the
dedicated flash programmer conflict. To prevent this,
isolate the signal on the device side.
Figure 17-6. Malfunction of Another Device
µ
If the signal output by the PD78F9436 or 78F9456 affects another device in the
flash memory programming mode, isolate the signal on the device side.
If the signal output by the dedicated flash programmer affects another
device, isolate the signal on the device side.
User's Manual U15075EJ2V1UD
µ
PD78F9436, 78F9456
Connection pin of dedicated flash
programmer
Other device
Output pin
Connection pin of dedicated flash
programmer
Other device
Input pin
Connection pin of dedicated flash
programmer
Other device
Input pin