NEC 78K0 Series User Manual page 567

(1) Signal collision
If the dedicated flash programmer (output) is connected to a pin (input) of a serial interface connected to another
device (output), signal collision takes place. To avoid this collision, either isolate the connection with the other
device, or make the other device go into an output high-impedance state.
78K0/KE2
Input pin
(2) Malfunction of other device
If the dedicated flash programmer (output or input) is connected to a pin (input or output) of a serial interface
connected to another device (input), a signal may be output to the other device, causing the device to malfunction.
To avoid this malfunction, isolate the connection with the other device.
78K0/KE2
78K0/KE2
CHAPTER 26 FLASH MEMORY
Figure 26-9. Signal Collision (Input Pin of Serial Interface)
Signal collision
In the flash memory programming mode, the signal output by the device
collides with the signal sent from the dedicated flash programmer.
Therefore, isolate the signal of the other device.
Figure 26-10. Malfunction of Other Device
Pin
If the signal output by the 78K0/KE2 in the flash memory programming
mode affects the other device, isolate the signal of the other device.
Pin
If the signal output by the dedicated flash programmer in the flash memory
programming mode affects the other device, isolate the signal of the other
device.
Preliminary User's Manual U17260EJ3V1UD
Dedicated flash programmer
connection pin
Other device
Output pin
Dedicated flash programmer
connection pin
Other device
Input pin
Dedicated flash programmer
connection pin
Other device
Input pin
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