Renesas RL78 Series User Manual page 805

RL78/G1D
26.8 Data Flash
26.8.1 Data flash overview
An overview of the data flash memory is provided below.
● The user program can rewrite the data flash memory by using the data flash library. For details, refer to RL78 Family
Data Flash Library User's Manual.
● The data flash memory can also be rewritten to through serial programming using the dedicated flash memory
programmer or an external device.
● The data flash can be erased in 1-block (1-Kbyte) units.
● The data flash can be accessed only in 8-bit units.
● The data flash can be directly read by CPU instructions.
● Instructions can be executed from the code flash memory while rewriting the data flash memory (that is, background
operation (BGO) is supported).
● Because the data flash memory is an area exclusively used for data, it cannot be used to execute instructions.
● Accessing the data flash memory is not possible while rewriting the code flash memory (during self-programming).
● Manipulating the DFLCTL register is not possible while rewriting the data flash memory.
● Transition to the STOP mode is not possible while rewriting the data flash memory.
Cautions 1. The data flash memory is stopped after a reset is canceled. The data flash control register
(DFLCTL) must be set up in order to use the data flash memory.
2. The high-speed on-chip oscillator should be kept operating during data flash rewrite. If it is kept
stopping, the high-speed on-chip oscillator clock should be operated (HIOSTOP = 0). The data
flash library should be executed after 30 µs have elapsed.
Remark For rewriting the code flash memory via a user program, see 26.6 Self-Programming.
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
CHAPTER 26 FLASH MEMORY
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