
HARDWARE
3850 Group (Spec. H) User’s Manual
FUNCTIONAL DESCRIPTION
1-43
Software Commands
Table 10 lists the software commands.
After setting the CPU rewrite mode select bit to “1”, write a software
command to specify an erase or program operation.
The content of each software command is explained below.
Read Array Command (FF16)
The read array mode is entered by writing the command code “FF16”
in the first bus cycle. When an 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–D7).
The read array mode is retained intact until another command is writ-
ten. And after power on and after recover from deep power down
mode, this mode is selected also.
Table 10 List of software commands (CPU rewrite mode)
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.
The status register is explained in the next section.
Clear Status Register Command (5016)
This command is used to clear the bits SR1,SR4 and SR5 of the
status register after they have been set. These bits indicate that op-
eration has ended in an error. To use this command, write the com-
mand code “5016” in the first bus cycle.
Command
Program
Clear status register
Read array
Read status register
X
First bus cycle
Second bus cycle
FF16
7016
5016
4016
Write
XSRD
Read
Write
Erase all block
X
2016
Write
X
2016
Write
(Note 1)
WA (Note 2)
WD (Note 2)
Block erase
X2016
Write
D016
Write
BA (Note 3)
Mode
Address
Mode
Address
Data
(D0 to D7)
Data
(D0 to D7)
(Note 4)
Notes 1: SRD = Status Register Data
2: WA = Write Address, WD = Write Data
3: BA = Block Address (Enter the maximum address of each block.)
4: X denotes a given address in the user ROM area .
Cycle number
1
2
1
2