Datasheet

Section 19 Flash Memory (0.35-μm F-ZTAT Version)
Rev.6.00 Mar. 18, 2009 Page 702 of 980
REJ09B0050-0600
19.6 On-Board Programming Modes
In an on-board programming mode, programming, erasing, and verification for the on-chip flash
memory can be performed. There are two on-board programming modes: boot mode and user
program mode. Table 19.4 shows how to select boot mode. User program mode can be selected by
setting the control bits by software. For a diagram that shows mode transitions of flash memory,
see figure 19.2.
Table 19.4 Setting On-Board Programming Mode
Mode Setting MD2 MD1 MD0
Boot mode Single-chip activation expanded mode
with on-chip ROM enabled
0 1 1
19.6.1 Boot Mode
When this LSI enters boot mode, the embedded boot program is started. The boot program
transfers the programming control program from the externally connected host to the on-chip
RAM via the SCI_1. When the flash memory is all erased, the programming control program is
executed.
Table 19.5 shows the boot mode operations between reset end and branching to the programming
control program.
1. When the boot program is initiated, the SCI_1 should be set to asynchronous mode, the chip
measures the low-level period of asynchronous 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 SCI_1 bit rate to match that of the host. The transfer format is 8-bit data, 1
stop bit, and no parity. 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 ends, it takes approximately 100
states before the chip is ready to measure the low-level period.
2. After matching the bit rates, the chip transmits one H'00 byte to the host to indicate the end 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 19.6.