
CHAPTER 27
μ
PD78F0134, 78F0138
User’s Manual U16228EJ2V0UD
450
(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.
Figure 27-15. Signal Collision (Input Pin of Serial Interface)
PD78F0134, 78F0138
μ
Input pin
Signal collision
Dedicated flash programmer
connection pin
Other device
Output pin
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.
(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.
Figure 27-16. Malfunction of Other Device
PD78F0134, 78F0138
μ
Pin
Dedicated flash programmer
connection pin
Other device
Input pin
If the signal output by the
PD78F0134 or 78F0138
in the flash memory
programming mode affects the other device, isolate the signal of the other
device.
Pin
Dedicated flash programmer
connection pin
Other device
Input 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.
μ
PD78F0134, 78F0138
μ