79
3886 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
G
Error check command
Input command code 80
16
in the first transfer, and the
M38869FFAHP/GP 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 information is 1, it indicates that a command error
has occurred. A command error means that some invalid com-
mands other than commands shown in Table 26 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 V
PP
pin input to the V
PP
L level to terminate
the serial input/output mode. Then, place the M38869FFAHP/GP
into the serial I/O mode back again. The serial communication cir-
cuit is reset by this operation and is ready to accept commands.
The error flag alone is not cleared by this operation, so the user
can examine 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. 78 Timings at error checking
Note:
The programming/erasing algorithm flow chart of the serial
I/O mode is the same as that of the parallel I/O mode. Re-
fer to Figure 71.
SCLK
BUSY
OE
SDA
E0
t
CH
Command code input (80
16
)
Error flag output
0 0 0 0 0 0 0 1
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”