M38B71M1 datasheet(93/110 Pages) RENESAS | SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

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38B7 Group

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS

q Error check command

Input command code 8016 in the first transfer, and the M38B79FF

outputs error information from the SDA pin, beginning at the next

falling edge of the serial clock. If the LSB bit of the 8-bit error infor-

mation is 1, it indicates that a command error has occurred. A

command error means that some invalid commands other than

commands shown in Table 20 has been input.

When a command error occurs, the serial communication circuit

sets the corresponding flag and stops functioning to avoid an erro-

neous programming or erase. When being placed in this state, the

serial communication circuit does not accept the subsequent serial

clock and data (even including an error check command). There-

fore, if the user wants to execute an error check command,

temporarily drop the VPP pin input to the VPPL level to terminate

the serial input/output mode. Then, place the M38B79FF into the

serial I/O mode back again. The serial communication circuit is re-

set by this operation and is ready to accept commands. The error

flag alone is not cleared by this operation, so the user can exam-

ine the serial communication circuit’s error conditions before reset.

This examination is done by the first execution of an error check

command after the reset. The error flag is cleared when the user

has executed the error check command. Because the error flag is

undefined immediately after power-on, always be sure to execute

the error check command.

Fig. 97 Timings at error checking

SCLK

BUSY

SDA

tCH

Command code input (8016)

Error flag output

00000001

??????

Note: When outputting the error flag, the SDA pin is switched for output at the first falling edge of the serial clock. The SDA pin is placed

in the floating state during the period of th(C-E) after the last rising edge of the serial clock (at the 8th bit).

“H”

“L”

M38B71M1 Datasheet(PDF) 93 Page - Renesas Technology Corp