SH7058 Datasheet, PDF (934/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

providing a reset input over a period longer than the normal 100 µs to reduce the damage to
flash memory.
23.8.3 Other 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 40 MHz, the download for each program takes approximately 75 µs at maximum.
2. User branch processing intervals
The intervals for executing the user branch processing differs in programming and erasing. The
processing phase also differs. Table 23.11 lists the maximum and minimum intervals for
initiating the user branch processing when the CPU clock frequency is 40 MHz.
Table 23.11 Initiation Intervals of User Branch Processing
Processing Name
Maximum Interval
Minimum Interval
Programming
Approximately 1 ms
Approximately 17 µs
Erasing
Approximately 5 ms
Approximately 17 µs
However, when operation is done with CPU clock of 40 MHz, maximum and minimum values of
the time until initial user branch processing are as shown in table 23.12.
Table 23.12 Initial User Branch Processing Time
Processing Name
Programming
Erasing
Max.
Approximately 113 µs
Approximately 85 µs
Min.
Approximately 113 µs
Approximately 45 µs
3. Write to flash-memory related registers by AUD or DMAC
While an instruction in on-chip RAM is being executed, the AUD or 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.
4. State in which AUD operation is disabled and interrupts are ignored
In the following modes or period, the AUD is in module standby mode and cannot operate.
The NMI or maskable interrupt requests are ignored; they are not executed and the interrupt
sources are not retained.
 Boot mode
 Programmer mode
Rev. 3.0, 09/04, page 893 of 1086