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CHAPTER 27 FLASH MEMORY
User’s Manual U17473EJ2V0UD
602
27.6.3 RESET pin
If the reset signal of the dedicated flash programmer is connected to the RESET pin that is connected to the reset
signal generator on the board, signal collision takes place. To prevent this collision, isolate the connection with the
reset signal generator.
If the reset signal is input from the user system while the flash memory programming mode is set, the flash
memory will not be correctly programmed. Do not input any signal other than the reset signal of the dedicated flash
programmer.
Figure 27-13. Signal Collision (RESET Pin)
RESET
Dedicated flash programmer
connection signal
Reset signal generator
Signal collision
Output pin
In the flash memory programming mode, the signal output by the reset
signal generator collides with the signal output by the dedicated flash
programmer. Therefore, isolate the signal of the reset signal generator.
78K0/LG2
27.6.4 Port pins
When the flash memory programming mode is set, all the pins not used for flash memory programming enter the
same status as that immediately after reset. If external devices connected to the ports do not recognize the port
status immediately after reset, the port pin must be connected to VDD or VSS via a resistor.
27.6.5 REGC pin
Connect the REGC pin to GND via a capacitor (0.47 to 1
μF: recommended) in the same manner as during normal
operation.
27.6.6 Other signal pins
Connect X1 and X2 in the same status as in the normal operation mode when using the on-board clock.
To input the operating clock from the dedicated flash programmer, however, connect as follows.
PG-FP4, FL-PR4:
Connect CLK of the programmer to EXCLK/X2/P122.
PG-FPL3, FP-LITE3:
Connect CLK of the programmer and X1/P121, and connect its inverted signal to
X2/EXCLK/P122.
Cautions 1. Only the internal high-speed oscillation clock (fRH) can be used when CSI10 is used.
2. Only the X1 clock (fX) or external main system clock (fEXCLK) can be used when UART6 is used.
3. For products without an on-chip debug function and with the flash memory of 48 KB or more
(
μPD78F0394, 78F0395, 78F0396, and 78F0397) , and having a product rank of “I” or “E”, and
for the product with an on-chip debug function (
μPD78F0397D), connect P31/INTP2/OCD1ANote
and P121/X1/OCD0A
Note
as follows when writing the flash memory with a flash memory
programmer.
P31/INTP2/OCD1ANote: Connect to VSS via a resistor (10 kΩ: recommended).
P121/X1/OCD0ANote:
When using this pin as a port, connect it to VSS via a resistor (10 k
Ω:
recommended) (in the input mode) or leave it open (in the output
mode).
The above connection is not necessary when writing the flash memory by means of self
programming.
Note OCD0A and OCD1A are provided to the
μPD78F0397D only.
Remark
For the product ranks, consult an NEC Electronics sales representative.
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