h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 818

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 21A ROM (H8S/2636 Group)
On-Chip RAM Area Divisions in Boot Mode: In boot mode, the RAM area is divided into an
area used by the boot program and an area to which the programming control program is
transferred via the SCI, as shown in figure 21A-9. The boot program area cannot be used until the
execution state in boot mode switches to the programming control program transferred from the
host.
Notes on Use of Boot Mode:
Rev. 6.00 Feb 22, 2005 page 758 of 1484
REJ09B0103-0600
Note: The boot program area cannot be used until a transition is made to the execution state for
When the chip comes out of reset in boot mode, it measures the low-level period of the input at
the SCI’s RxD1 pin. The reset should end with RxD1 high. After the reset ends, it takes
approximately 100 states before the chip is ready to measure the low-level period of the RxD1
pin.
In boot mode, if any data has been programmed into the flash memory (if all data is not 1), all
flash memory blocks are erased. Boot mode is for use when user program mode is unavailable,
such as the first time on-board programming is performed, or if the program activated in user
program mode is accidentally erased.
Interrupts cannot be used while the flash memory is being programmed or erased.
The RxD1 and TxD1 pins should be pulled up on the board.
the programming control program transferred to RAM. Note also that the boot program
remains in this area of the on-chip RAM even after control branches to the programming
control program.
Figure 21A-9 RAM Areas in Boot Mode
H'FFE000
H'FFE7FF
H'FFE800
H'FFEFBF
control program area
Boot program area
Programming
(1.9 kbytes)
(2 kbytes)