m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 412

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

software commands. Therefore, this mode allows the user to reprogram the contents of the user ROM area
with the microcomputer mounted on the final printed circuit board, without using any ROM programmer.
advance. In the flash memory CPU reprogramming mode, however, an opcode cannot be fetched for the
internal flash memory. Accordingly, be sure to transfer the reprogramming control software to an area other
than the internal flash memory area (e.g. the internal RAM area), and then execute the software in this area.
For details of each command, refer to section “19.2.4 Software commands.”
ROM area, 16 bits at a time. At writing of software command codes, the high-order 8 bits (D
ignored. (Except for the write data at the 2nd bus cycle of the programming command code.)
19.2 Flash memory CPU reprogramming mode
In this mode, the user ROM area can be reprogrammed by the central processing unit (CPU) executing
Be sure to store the reprogramming control software into the user ROM area or the boot ROM area in
The flash memory CPU reprogramming mode is available in any of the single-chip and boot modes.
The software commands listed in Table 19.2.1 can be used in the flash memory CPU reprogramming mode.
Note that commands and data must be read from and written into even-numbered addresses within the user
Table 19.2.1 Software commands
SRD : Status register data (D
WA : Write address (A
WD : Write data (16 bits)
BA
Read Array
Read Status Register
Clear Status Register
Programming
Block Erase
Erase All Blocks
: The highest address of a block (Note that A
: Arbitrary even-numbered address in user ROM area (A
Software commands
7
to A
0
0
to be incremented by 2 from “00
to D
7
)
7905 Group User’s Manual Rev.1.0
Mode
Write
Write
Write
Write
Write
Write
0
19.2 Flash memory CPU reprogramming mode
= 0.)
1st bus cycle
Address
FLASH MEMORY VERSION
0
16
= 0)
” to “FE
(D
Data
FF
0
70
50
40
20
20
16
to D
”)
16
16
16
16
16
16
7
)
Mode
Read
Write
Write
Write
—
—
2nd bus cycle
Address
WA
BA
—
—
8
to D
SRD
D0
20
Data
WD
15
—
—
) are
16
16
19-9