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M38B71M1 Datasheet(PDF) 93 Page - Renesas Technology Corp |
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M38B71M1 Datasheet(HTML) 93 Page - Renesas Technology Corp |
93 / 110 page ![]() 92 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 OE SDA E0 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” |