HD64F3437TF16 Datasheet, PDF (546/752 Pages) Hitachi Semiconductor – 12 V must not be applied to the S-mask model (single-power-supply specification), as this may permanently damage the device.

H'F780
User program
transfer area
(1664 bytes)
H'FDFF
H'FF00
H'FF7F
Boot program
area*
(128 bytes)
Note: * This area cannot be used until the H8/3437SF starts to execute the user program
transferred to RAM. Note that even after the branch to the user program, the boot
program area still contains the boot program.
Figure 21.9 RAM Areas in Boot Mode
Notes on Use of Boot Mode
1. When the H8/3437SF comes out of reset in boot mode, it measures the low period of the input
at the SCI’s RxD₁ pin. The reset should end with RxD₁ high. After the reset ends, it takes about
100 states for the H8/3437SF to get ready to measure the low period of the RxD₁ input.
2. In boot mode, if any data has been programmed into the flash memory (if all data is not H'FF),
all flash memory blocks are erased. Boot mode is for use when user programming mode is
unavailable, such as the first time on-board programming is performed, or if the program
activated in user programming mode is accidentally erased.
3. Interrupts cannot be used while the flash memory is being programmed or erased.
4. The RxD₁ and TxD₁ pins should be pulled up on-board.
5. Before branching to the user program (at address H'E880 in the RAM area), the H8/3437SF
terminates transmit and receive operations by the on-chip SCI (by clearing the RE and TE bits
of serial control register SCR to 0 in channel 1), but the auto-aligned bit rate remains set in bit
rate register BRR. The transmit data output pin (TxD₁) is in the high output state (in port 8, bits
P8₄DDR of the port 8 data direction register and P8₄DR of the port 8 data register are set to 1).
517