38D2 datasheet(83/136 Pages) RENESAS

83 / 136 page

Rev.3.02

Apr 10, 2008

Page 83 of 131

REJ03B0177-0302

38D2 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, program,

erase, etc.) the internal flash memory. This I/O is clock

synchronized serial. This mode requires a purpose-specific

peripheral 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 by connecting “H” to the CNVSS pin

and “H” to the P32 (BOOTENT) pin, and releasing the reset

operation. (In the ordinary 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 standard serial I/O mode 2 of the

clock asynchronous serial. Tables 19 and 20 show description of

pin function (standard serial I/O mode). Figure 80 to 82 show the

pin connections for the standard serial I/O mode.

In standard serial I/O mode, only the User ROM area shown in

Figure 70 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

written in the flash memory match. The commands sent from the

peripheral unit (programmer) are not accepted unless the ID code

matches.

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