FLASH MEMORY VERSION
19.2 Flash memory CPU reprogramming mode
19.2.4 Software commands
Software commands are described below.
Software commands and data must be read from and written into even-numbered addresses in the user
ROM area, 16 bits at a time. At writing of a command code, the high-order 8 bits (D to D15) are ignored.
8
(1) Read array command
Writing command code “FF16” at the 1st bus cycle pushes the microcomputer into the read array mode.
When an address to be read is input at the next and the following bus cycles, the contents at the
specified address are output to the data bus (D to D15), 16 bits at a time.
0
The read array mode is maintained until another software command is written.
(2) Read status register command
Writing command code “7016” at the 1st bus cycle outputs the contents of the status register to the
data bus (D
0
to D ) by a read at the 2nd bus cycle. (See Table 19.2.2.)
7
(3) Clear status register command
Writing command code “5016” at the 1st bus cycle clears two bits (SR.4 and SR.5) of the status register
to “0.” (See Table 19.2.2.)
(4) Programming
This command executes programming, one word
at a time. Write command code “4016” at the
Start
1st bus cycle and then write data at the 2nd
bus cycle, 16 bits at a time. After writing of
one word has been completed, the automatic
Command code
“4016” is written.
programming (programming and verification of
data) operation is initiated. During the automatic
programming operation, be sure not to access
the flash memory or not to execute the next
Data is written to an
arbitrary write address.
command. The completion of the automatic
programming can be recognized by the RY/BY
status bit (bit 0 at address 9E16).
RY/BY status bit = “1”?
(bit 0 at address 9E16
)
NO
After the automatic programming operation has
been completed, the result of it can be
recognized by reading out the status register.
(Refer to section “19.2.5 Full status check.”)
Figure 19.2.3 shows the programming operation
flowchart.
YES
••• See Figure 19.2.6.
Full status check
Programming
operation is completed.
Note that, for the areas having already been
programmed, be sure to program after an erase
(block erase) operation. If the programming
command is executed for the areas having
already been programmed, no programming error
will occur, but the contents of the areas become
undefined.
Fig. 19.2.3 Programming operation flowchart
7906 Group User’s Manual Rev.2.0
19-14
RENESAS [ RENESAS TECHNOLOGY CORP ]
