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7542 Group
Standard serial I/O Mode
The standard serial I/O mode inputs and outputs the software
commands, addresses and data needed to operate (read, pro-
gram, erase, etc.) the internal flash memory. This I/O is clock
synchronized serial. This mode requires a purpose-specific pe-
ripheral unit.
The standard serial I/O mode is different from the parallel I/O
mode in that the CPU controls flash memory rewrite (uses the
CPU rewrite mode), rewrite data input and so forth. The standard
serial I/O mode is started when the microcomputer is reset and
the CNV
pin high after pulling the P3
SS
high, P0
/S
pin low and P0
6
CLK2
microcomputer mode, set CNVss pin to "L" level.)
This control program is written in the Boot ROM area when the
product is shipped from Renesas. Accordingly, make note of the
fact that the standard serial I/O mode cannot be used if the Boot
ROM area is rewritten in parallel I/O mode.
The standard serial I/O mode has standard serial I/O mode 1 of
the clock synchronous serial and the standard serial I/O mode 2 of
the clock asynchronous serial.
Table 11 lists the description of pin function (standard serial I/O
mode 1). Figures 104 to 106 show the pin connections for the
standard serial I/O mode 1.
Table 12 lists the description of pin function (standard serial I/O
mode 2). Figures 109 to 111 show the pin connections for the
standard serial I/O mode 2.
In standard serial I/O mode, only the User ROM area shown in
Figure 94 can be rewritten. The Boot ROM area cannot be written.
In standard serial I/O mode, a 7-byte ID code is used. When there
is data in the flash memory, this function determines whether the
ID code sent from the peripheral unit (programmer) and those writ-
ten in the flash memory match.The commands sent from the
peripheral unit (programmer) are not accepted unless the ID code
matches.
Rev.3.02
Oct 31, 2006
REJ03B0006-0302
(RP) pin low, P3
(CE) pin
7
2
/TxD
pin high. (In the ordinary
5
2
Page 84 of 134
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