Renesas M16C/26 Series Reference Book page 27

Under development
Preliminary specification
Specifications in this manual are tentative and subject to change.
M16C/26 Group
1.10 Precautions for Flash Memory Version
1.10.1 Precautions for Functions to Inhibit Rewriting Flash Memory Rewrite
ID codes are stored in addresses 0FFFDF
and 0FFFFB . If wrong data are written to theses addresses, the flash memory cannot be read or written
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in standard serial I/O mode.
The ROMCP register is mapped in address 0FFFFF
memory cannot be read or written in parallel I/O mode.
In the flash memory version of microcomputer, these addresses are allocated to the vector addresses (H)
of fixed vectors.
1.10.2 Precautions for Stop mode
When shifting to stop mode, the following settings are required:
• Set the FMR01 bit to "0" (CPU rewrite mode disabled) and disable DMA transfers before setting the
CM10 bit to "1" (stop mode).
• Execute the JMP.B instruction subsequent to the instruction which sets the CM10 bit to "1" (stop
mode)
Example program
1.10.3 Precautions for Wait mode
When shifting to wait mode, set the FMR01 bit to "0" (CPU rewrite mode diabled) before executing the
WAIT instruction.
1.10.4 Precautions for Low power dissipation mode, ring oscillator low power dissipation mode
If the CM05 bit is set to "1" (main clock stop), the following commands must not be executed.
• Program
• Block erase
1.10.5 Writing command and data
Write the command code and data at even addresses.
1.10.6 Precautions for Program Command
Write 'xx40 ' in the first bus cycle and write data to the write address in the second bus cycle, and an
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auto program operation (data program and verify) will start. Make sure the address value specified in the
first bus cycle is the same even address as the write address specified in the second bus cycle.
Rev.0.90 2003.12.28 page 22 of 28
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BSET 0, CM1
JMP.B L1
L1:
Program after returning from stop mode
1.10 Precautions for Flash Memory Version
, 0FFFE3 , 0FFFEB , 0FFFEF
16 16
. If wrong data is written to this address, the flash
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; Stop mode
, 0FFFF3 , 0FFFF7
16 16 16
,