Datasheet

Section 19 Flash Memory (0.35-μm F-ZTAT Version)
Rev.6.00 Mar. 18, 2009 Page 703 of 980
REJ09B0050-0600
3. When boot mode is used, the flash memory programming control program must be prepared in
the host beforehand. Prepare a programming control program in accordance with the
description in section 19.7, Flash Memory Programming/Erasing.
4. Before branching to the programming control program, the chip terminates transfer operations
by the SCI_1 (by clearing the RE and TE bits in SCR to 0), but the adjusted bit rate value
remains set in BRR. Therefore, the programming control program can still use it for transfer
of program data or verify data with the host. The TxD pin is high. The contents of the CPU
general registers are undefined immediately after branching to the programming control
program. These registers must be initialized at the beginning of the programming control
program, since the stack pointer (SP), in particular, is used implicitly in subroutine calls, etc.
5. In boot mode, if flash memory contains data (all data is not 1), all blocks of flash memory are
erased. Boot mode is used for the initial programming in the on-board state or for a forcible
return when a program that is to be initiated in user program mode was accidentally erased
and could not be executed in user program mode.
Notes: 1. In boot mode, a part of the on-chip RAM area (H'FF8000 to H'FF87FF) is used by the
boot program. Addresses H'FF8800 to H'FFBFFF is the area to which the
programming control program is transferred from the host. The boot program area
cannot be used until the execution state in boot mode switches to the programming
control program.
2. Boot mode can be cleared by a reset. Release the reset by setting the MD pins, after
waiting at least 20 states since driving the reset pin low. Boot mode is also cleared
when the WDT overflow reset occurs.
3. Do not change the MD pin input levels in boot mode.
4. All interrupts are disabled during programming or erasing of the flash memory.