Datasheet

78K0/Ix2 CHAPTER 25 FLASH MEMORY
R01UH0010EJ0500 Rev.5.00 655
Feb 28, 2012
25.4 Connection of Pins on Board
To write the flash memory on-board, connectors that connect the dedicated flash memory programmer must be
provided on the target system. First provide a function that selects the normal operation mode or flash memory
programming mode on the board.
When the flash memory programming mode is set, all the pins not used for programming the flash memory are in the
same status as immediately after reset. Therefore, if the external device does not recognize the state immediately after
reset, the pins must be handled as described below.
25.4.1 TOOL pins
T
he pins used for communication in flash memory programming mode are shown in the table below.
Table 25-3. Pins Used for Communication in Flash Memory Programming Mode
Pin Name Connection of Pins
TOOLC0, TOOLC1
Connect this pin directly to the dedicated flash
memory programmer or pull it down by connecting it
to VSS via a resistor (10 k)
TOOLD0, TOOLD1
Connect this pin directly to the dedicated flash
memory programmer or pull it up by connecting it to
V
DD via a resistor (3 k to 10 k)
To connect the dedicated flash memory programmer to the pins of a serial interface that is connected to another device
on the board, care must be exercised so that signals do not collide or that the other device does not malfunction.
(1) Signal collision
If the dedicated flash memory programmer is connected to the TOOL pin that is connected to another device, signal
collision takes place. To avoid this collision, either isolate the connection with the other device, or make the other
device go into a high-impedance state.
Figure 25-3. Signal Collision (TOOL Pin)
TOOL pin
Signal collision
Dedicated flash
memory
programmer connection pin
Other device
Input pin or
output pin
In the flash memory programming mode, the signal of the other device
collides with the signal of the dedicated flash programmer. Therefore,
isolate the signal of the other device.
78K0/Ix2
microcontrollers