Renesas M16C/64A Series User Manual page 829

M16C/64A Group
32.23.4 User Boot
32.23.4.1 User Boot Mode Program
Note the following when using user boot mode:
•
When using user boot mode, make sure to allocate the program to be executed to program ROM 2.
•
Bits VDSEL1 and LVDAS in the OFS1 address are disabled in boot mode.
•
When restarting the MCU in user boot mode after starting it in user boot mode, RAM becomes
undefined.
•
If addresses 13FF8h to 13FFBh are all 00h, the MCU does not enter standard serial I/O mode.
Therefore, the programmer or on-chip debugger cannot be connected.
•
As the reset sequence differs, the time necessary for starting the program is longer than in single-
chip mode.
•
Functions in user boot mode cannot be debugged by the on-chip debugging emulator or full spec
emulator.
•
While using user boot mode, do not change the input level of the pin used for user boot entry. How-
ever, if there is a possibility that the input level may change, perform the necessary processes in
user boot mode, then restart the MCU in single-chip mode before the input level changes.
•
To use user boot mode after standard serial I/O mode, turn off the power when exiting standard
serial I/O mode, and then turn on the power again (cold start). The MCU enters user boot mode
under the right conditions.
32.23.5 EW1 Mode
(Technical update number: TN-16C-A175A/E)
Adhere to the following when using EW1 mode:
32.23.5.1 Frequency Limitation of EW1 Mode
Set the CPU clock to 1 MHz or higher when using EW1 mode.
32.23.5.2 Frequency Limitation of Block Blank Check Command
Set the CPU clock to 3 MHz or higher when using the block blank check command.
32.23.5.3 Disabling the Lock Bit
Set the FMR02 bit in the FMR0 register to 1 (lock bit disabled).
Do not execute the read lock bit status command or lock bit program command.
32.23.5.4 Entering EW1 Mode in the User Program Using Wait or Stop Mode
When using EW1 mode in the user program in which the MCU enters wait mode or stop mode, set
the FMSTP bit in the FMR0 register to 1 (flash memory off) on RAM. Then, set the FMSTP bit to 0
(flash memory on) again and enter the EW1 mode on flash memory. Execute these processes while
an interrupt is disabled.
R01UH0136EJ0210 Rev.2.10
Jul 31, 2012
32. Usage Notes
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