
CHAPTER 27
μ
PD78F0134, 78F0138
User’s Manual U16228EJ2V0UD
449
27.6
Handling of Pins on Board
To write the flash memory on-board, connectors that connect the dedicated flash 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.
27.6.1 V
PP
pin
In the normal operation mode, the V
PP
pin is connected to V
SS
. In addition, a write voltage of 10.0 V (TYP.) is
supplied to the V
PP
pin in the flash memory programming mode. Perform the following pin handling.
(1) Connect pull-down resistor R
VPP
= 10 k
to the V
PP
pin.
(2) Switch the input of the V
PP
pin to the programmer side by using a jumper on the board or to GND directly.
Figure 27-14. Example of Connection of V
PP
Pin
PD78F0134, 78F0138
μ
V
PP
Dedicated flash programmer connection pin
Pull-down resistor (R
VPP
)
27.6.2 Serial interface pins
The pins used by each serial interface are listed below.
Table 27-6. Pins Used by Each Serial Interface
Serial Interface
Pins Used
CSI10
SO10, SI10, SCK10
CSI10 + HS
SO10, SI10, SCK10, HS/P15
UART0
TxD0, RxD0
UART0 + HS
TxD0, RxD0, HS/P15
UART6
TxD6, RxD6
To connect the dedicated flash 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.