hd64338342hw Renesas Electronics Corporation., hd64338342hw Datasheet - Page 214

• Manufacturer Part Number: hd64338342hw
• Description: Renesas 8-bit Single-chip Microcomputer H8 Family/h8/300l Super Low Power Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 ROM
6.7.1
Table 6.9 shows the boot mode operations between reset end and branching to the programming
control program. The device uses SCI32 in the boot mode.
1. When boot mode is used, the flash memory programming control program must be prepared in
2. SCI3 should be set to asynchronous mode, and the transfer format as follows: 8-bit data, 1 stop
3. When the boot program is initiated, the chip measures the low-level period of asynchronous
4. After matching the bit rates, the chip transmits one H'00 byte to the host to indicate the
5. In boot mode, a part of the on-chip RAM area is used by the boot program. The area H'F780 to
6. Before branching to the programming control program, the chip terminates transfer operations
7. Boot mode can be cleared by a reset. End the reset after driving the reset pin low, waiting at
Rev. 6.00 Aug 04, 2006 page 178 of 680
REJ09B0145-0600
the host beforehand. Prepare a programming control program in accordance with the
description in section 6.8, Flash Memory Programming/Erasing.
bit, and no parity. The inversion function of TXD and RXD pins by the SPCR register is set to
“Not to be inverted,” so do not put the circuit for inverting a value between the host and this
LSI.
SCI communication data (H'00) transmitted continuously from the host. The chip then
calculates the bit rate of transmission from the host, and adjusts the SCI3 bit rate to match that
of the host. The reset should end with the RXD pin high. The RXD and TXD pins should be
pulled up on the board if necessary. After the reset is complete, it takes approximately 100
states before the chip is ready to measure the low-level period.
completion of bit rate adjustment. The host should confirm that this adjustment end indication
(H'00) has been received normally, and transmit one H'55 byte to the chip. If reception could
not be performed normally, initiate boot mode again by a reset. Depending on the host's
transfer bit rate and system clock frequency of this LSI, there will be a discrepancy between
the bit rates of the host and the chip. To operate the SCI properly, set the host's transfer bit
rate and system clock frequency of this LSI within the ranges listed in table 6.10.
H'FEEF 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.
by SCI3 (by clearing the RE and TE bits in SCR to 0), however the adjusted bit rate value
remains set in BRR. Therefore, the programming control program can still use it for transfer
of write data or verify data with the host. The TXD pin is high (PCR42 = 1, P42 = 1). 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, as the stack pointer (SP), in particular, is used implicitly in
subroutine calls, etc.
least 20 states, and then setting the TEST pin and P24 pin. Boot mode is also cleared when a
WDT overflow occurs.
Boot Mode