h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 717

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

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 20.8. 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:
• When the chip comes out of reset in boot mode, it measures the low-level period of the input at
• In boot mode, if any data has been programmed into the flash memory (if all data is not 1), all
• 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.
• Before branching to the programming control program (RAM area H'FFE7FF), the chip
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.
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.
terminates transmit and receive operations by the on-chip SCI (channel 1) (by clearing the RE
Note: The boot program area cannot be used until a transition is made to the execution state
for 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 20.8 RAM Areas in Boot Mode
H'FFE000
H'FFE7FF
H'FFEFBF
control program area
Boot program area
Programming
(1.9 kbytes)
(2 kbytes)
Rev. 5.00 Sep 22, 2005 page 691 of 1136
REJ09B0257-0500
Section 20 ROM