M16C26 Datasheet, PDF (202/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

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Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative and subject to change.
CPU Rewrite Mode (Flash Memory Version)
M16C/26 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Software Commands
Table 1.20.1 lists the software commands available with the M16C/26 (flash memory version).
After setting the CPU rewrite mode select bit to 1, write a software command to specify an erase or
program operation. Note that when entering a software command, the upper byte (D8 to D15) is ignored.
The content of each software command is explained below.
The first bus cycle commands must be written to an even address in the user ROM area.
Table 1.20.1. List of software commands (CPU rewrite mode)
Command
Read array
Read status register
Clear status register
Program
(Note 3)
Block erase
Mode
Write
Write
Write
Write
Write
First bus cycle
Address
Data
(D0 to D7)
X
FF16
X
7016
X
5016
WA
4016
X
2016
S econd bus cycle
Mode
Address
Data
(D0 to D7)
Read
X
SRD ^{(Note 2)}
Write
Write
WA ^{(Note 3)} WD ^{(Note 3)}
BA ^{(Note 4)} D016
Note 1: When a software command is input, the high-order byte of data (D8 to D15) is ignored.
Note 2: SRD = Status Register Data (Set an address to even address in the user ROM area)
Note 3: WA = Write Address (even address), WD = Write Data (16-bit data)
Note 4: BA = Block Address (Enter the maximum address of each block that is an even address.)
Note 5: X denotes a given address in the user ROM area (that is an even address).
Read Array Command (FF16)
The read array mode is entered by writing the command code “FF16” in the first bus cycle. When an
even address to be read is input in one of the bus cycles that follow, the content of the specified
address is read out at the data bus (D0–D15), 16 bits at a time.
The read array mode is retained intact until another command is written.
However, please begin to read data in the following procedures when a user uses read array com-
mand after program command.
(1) Set FF16, FF16, FF16, FF16 to arbitrary continuing four address beforehand
(2) Input the top address which FF16 was set at (in read array mode)
(3) Input the top address till FFFF16 agrees with the value that begins to have been read
(4) Input top address +2
(5) Input top address +2 till FFFF16 agrees with the value that begins to have been read
(6) Input an arbitrary address
Read Status Register Command (7016)
When the command code “7016” is written in the first bus cycle, the content of the status register is
read out at the data bus (D0–D7) by a read in the second bus cycle (Set an address to even address
in the user ROM area).
The status register is explained in the next section.
In EW1 mode, cannot use read status register command.
Clear Status Register Command (5016)
This command is used to clear the bits SR4 and SR5 of the status register after they have been set.
These bits indicate that operation has ended in an error. To use this command, write the command
code “5016” in the first bus cycle.
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