3069RF-ZTAT Datasheet, PDF (658/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

18.8.1 Usage Notes
1. Download time of on-chip program
The programming program that includes the initialization routine and the erasing program that
includes the initialization routine are each 2 kbytes or less. Accordingly, when the CPU clock
frequency is 25 MHz, the download for each program takes approximately 164µs at
maximum.
2. Write to flash-memory related registers by DMAC
While an instruction in on-chip RAM is being executed, the DMAC can write to the SCO bit
in FCCS that is used for a download request or FMATS that is used for MAT switching. Make
sure that these registers are not accidentally written to, otherwise an on-chip program may be
downloaded and damage RAM or a MAT switchover may occur and the CPU get out of
control. Do not use DMAC to program FLASH related registers.
3. Compatibility with programming/erasing program of conventional F-ZTAT H8
microcomputer
A programming/erasing program for flash memory used in the conventional F-ZTAT H8
microcomputer which does not support download of the on-chip program by a SCO transfer
request cannot run in this LSI.
Be sure to download the on-chip program to execute programming/erasing of flash memory in
this LSI.
4. Monitoring runaway by WDT
Unlike the conventional F-ZTAT H8 microcomputer, no countermeasures are available for a
runaway by WDT during programming/erasing by the downloaded on-chip program.
Prepare countermeasures (e.g. use of the user branch routine and periodic timer interrupts) for
WDT while taking the programming/erasing time into consideration as required.
Rev. 5.0, 09/04, page 636 of 978