Renesas rl78 User Manual

 

RL78/G1A 

CHAPTER  25   FLASH  MEMORY 

 

To write the flash memory on-board by using the flash memory programmer, 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. 

 

Remark   For the flash memory programming mode, see 25.4.2  Flash memory programming mode. 

<R> 

 

In the flash memory programming mode, connect this pin to the dedicated flash memory programmer via an external 1 

k

Ω pull-up resistor. 

When this pin is used as the port pin, use that by the following method. 

 

When used as an input pin: 

Input of low-level is prohibited for t

HD

 period after external pin reset release.  However, 

when this pin is used via pull-down resistors, use the 500 k

Ω or more resistors. 

<R> 

When used as an output pin:  When this pin is used via pull-down resistors, use the 500 k

Ω or more resistors. 

 

Remarks  1.  t

HD

: How long to keep the TOOL0 pin at the low level from when the external and internal resets end for 

setting of the flash memory programming mode (see 29.9 or 30.9  Timing Specs for Switching Flash 

Memory Programming Modes) 

<R> 

 

  2.  The SAU and IICA pins are not used for communication between the RL78 microcontroller and 

dedicated flash memory programmer, because single-line UART (TOOL0 pin) is used. 

 

Signal conflict will occur if the reset signal of the dedicated flash memory programmer and external device are 

connected to the RESET pin that is connected to the reset signal generator on the board.  To prevent this conflict, isolate 

the connection with the reset signal generator. 

The flash memory will not be correctly programmed if the reset signal is input from the user system while the flash 

memory programming mode is set.  Do not input any signal other than the reset signal of the dedicated flash memory 

programmer and external device. 

 

 

Input pin

Dedicated flash memory programmer 
connection pin

Another device

Signal conflict

Output pin

In the flash memory programming mode, a signal output by another device 
will conflict with the signal output by the dedicated flash memory 
programmer.  Therefore, isolate the signal of another device.

RL78 microcontroller

 

 

R01UH0305EJ0200  Rev.2.00 

 

 

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Jul 04, 2013