RX610 Group
26. ROM (Flash Memory for Code Storage)
R01UH0032EJ0120 Rev.1.20
Page 836 of 1006
Feb 20, 2013
26.2.10
Flash Reset Register (FRESETR)
b7
b6
b5
b4
b3
b2
b1
b0
Value after reset:
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
FRESET
Address: 007F FFB6h
b15
b14
b13
b12
b11
b10
b9
b8
Value after reset:
0
0
0
0
0
0
0
0
FRKEY[7:0]
Bit
Symbol
Bit Name
Description
R/W
b0
FRESET
Flash Reset
0: FCU is not reset
1: FCU is reset
R/W
b7 to b1
Reserved
These bits are always read as 0. The write value should always be 0.
R/W
b15 to b8
FRKEY[7:0]
Key Code
These bits are used to enable or disable rewriting of the FRESET bit.
R/(W)
*
Note:
*
Write data is not retained.
FRESETR is a register to initialize the FCU.
Only specific values written to the upper byte in word access are valid. Data written to the upper byte is not retained.
When on-chip ROM is disabled, the data read from FRESETR is 0000h and writing is disabled.
FRESETR is initialized by a reset.
FRESET Bit (Flash Reset)
When the FRESET bit is set to 1, programming/erasure operations for the ROM/data flash are forcibly terminated, and
the FCU is initialized.
High voltage is applied to the memory of the ROM/data flash during programming/erasure. To ensure time required for
dropping the voltage applied to the memory, keep the FRESET bit set to 1 for tRESW2 (see section 28, Electrical
Characteristics) when initializing the FCU. While the FRESET bit is kept 1, prohibit the ROM/data flash from being read.
Additionally, when the FRESET bit is set to 1, the FCU commands cannot be used because FENTRYR is initialized.
Writing of the FRESET bit is enabled only in word access and when the FRKEY[7:0] bits are CCh.
FRKEY[7:0] Bits (Key Code)
These bits are used to enable or disable rewriting of the FRESET bit.
Data written to the FRKEY[7:0] bits is not retained.