Table of Contents
Advertisement
CHAPTER 17 FLASH MEMORY
17.4
Starting the Flash Memory Automatic Algorithm
Flash memory has an automatic algorithm. Writing to and erasing from flash memory
are executed by starting the automatic algorithm.
●
Command Operation
To start the automatic algorithm, write halfword (16-bit) data into the flash memory once to six times
consecutively. It will be referred to as command. The flash memory is reset to read mode when illegal
address are data are written to it, or address and data are written in the wrong order.
Table 17.4-1 shows the command list for flash memory write/erase.
Table 17.4-1 Command List
First write cycle
Command
Number of
sequence
accesses
Address
XXXX
Read/Reset
1
D5557
Read/Reset
4
D5557
Program
4
D5557
Chip erase
6
D5557
Sector erase
6
Temporary sector erase stop
Sector erase restart
D5557
Auto Select
3
Continuous
D5557
3
mode
Continuous
XXXX
2
write
Continuous
XXXX
2
mode reset
The commands are the same for word mode and byte mode. The data of bits that are not listed in the table
is arbitrary.
RA: Read address
PA: Write address
SA: Sector address (Specify any address in a sector.)
RD: Read data
PD: Write data
416
Second write cycle
Data
Address
Data
F0
-
-
H
H
AA
CAAAB
55
H
H
H
H
AA
CAAAB
55
H
H
H
H
AA
CAAAB
55
H
H
H
H
AA
CAAAB
55
H
H
H
H
When Address=XXXX
When Address=XXXX
AA
CAAAB
55
H
H
H
H
AA
CAAAB
55
H
H
H
H
A0
PA
PD
H
H
90
XXXX
F0
or 00
H
H
H
H
Fourth write/read
Third write cycle
cycle
Address
Data
Address
-
-
-
D5557
F0
RA
H
H
D5557
A0
PA
H
H
D5557
80
D5557
H
H
H
D5557
80
D5557
H
H
H
and Data=B0
are inputted, erasing of the sector currently being erased is
H
H
temporarily stopped.
and Data=30
are inputted, erasing is restarted after erasing of the sector
H
H
has been temporarily stopped.
D5557
90
-
H
H
D5557
20
-
H
H
-
-
-
-
-
-
H
Fifth write cycle
Sixth write cycle
Data
Address
Data
Address
-
-
-
RD
-
-
PD
-
-
AA
CAAAB
55
D5557
H
H
H
AA
CAAAB
55
SA
H
H
H
-
-
-
-
-
-
-
-
-
-
-
-
Data
-
-
-
-
-
-
10
H
H
30
H
-
-
-
-
-
-
-
-
Advertisement
Table of Contents
