
Preliminary Data Sheet
15
μ
PD29F008AL-X
4.2 Read / Reset
This command resets the device to the read mode.
When the device is in the read mode, no command is necessary for reading data. Data read can be performed
using the read cycle of a standard microprocessor.
The read mode is maintained until the contents of the command register are changed.
4.3 Read Product ID code
This command is used to read the manufacturer code or the device code of the device.
The manufacturer code (10H) is output by inputting 00000H in the address using the fourth write cycle. The device
code is output when 00001H is input.
The manufacturer code and device code can be read by selecting the read product ID code mode by applying V
ID
to
the A9 pin (See section
3.8 Read Product ID Code
). However, applying a high voltage to the address pin is not
desirable due to system design considerations. Using this command allows reading the manufacturer code and
device code without applying a high voltage to the pin.
4.4 Program
This command is used to program data.
Program is performed in 1-byte units. Program can be performed regardless of the address sequence, even if the
sector limit is exceeded. However, "0" cannot be changed back into "1" through the program operation. If overwriting
"1" to "0" is attempted, the program operation is interrupted and "1" is output to I/O5, or successful program is
indicated in data polling, but actually the data is "0" as before.
Following write by command sequence, the pulse required for program is automatically generated inside the device
and program verification is automatically performed, so that control from external is not required.
During automatic program, all commands that have been written are ignored. However, automatic program is
interrupted when hardware reset is performed. Since the programmed data is not guaranteed in this case, reexecute
the program command following completion of reset.
Upon completion of automatic program, the device returns to the read mode.
The operation status of automatic program can be determined by using the hardware sequence flags (I/O7, I/O6, RY
(/BY) pins).
See sections
5.1 I/O7 (Data Polling)
,
5.2 I/O6 (Toggle Bit)
, and
5.6 RY (/BY) (Ready / Busy)
.
Figure 4-1. Program Flow Chart
Start
Write program
command sequence
I/O7 = Data
Yes
No
Data poll from system
Increment address
Yes
No
Last address
Programing
completed