
LE25S40MB
10. Silicon ID Read
ID read is an operation that reads the manufacturer code and device ID information. The silicon ID read command is not
accepted during writing. There are two methods of reading the silicon ID, each of which is assigned a device ID. In the
first method, the read command sequence consists only of the first bus cycle in which (9Fh) is input. In the subsequent
bus cycles, the manufacturer code 62h which is assigned by JEDEC, 2-byte device ID code (memory type, memory
capacity), and reserved code are output sequentially. The 4-byte code is output repeatedly as long as clock inputs are
present, "Table 7-1 JEDEC ID code " lists the silicon ID codes and "Figure 15-a JEDEC ID read" shows the JEDEC ID
read timing waveforms.
The second method involves inputting the ID read command. This command consists of the first through fourth bus
cycles, and the one bite silicon ID can be read when 24 dummy bits are input after (ABh). "Table 7-2 ID code " lists the
silicon ID codes and "Figure 15-b ID read" shows the ID read timing waveforms.
If the SCK input persists after a device code is read, that device code continues to be output. The data output is
transmitted starting at the falling edge of the clock for bit 0 in the fourth bus cycle and the silicon ID read sequence is
finished by setting CS high.
Table 7-1 JEDEC ID code
Output code
Table 7-2 ID code
Output Code
Manufacturer code
Memory type
2 byte device ID
Memory capacity code
Device code
1
62h
16h
13h(4M Bit)
00h
1 byte device ID
3E
(LE25S40MB)
Figure 15-a JEDEC ID Read
CS
Mode3
0 1 2 3 4 5 6 7 8
15 16
23 24
31 32
39
SCK
Mode0
8CL
SI
9Fh
SO
High Impedance
62h
MSB
16h
MSB
13h
MSB
00h
MSB
62h
MSB
Figure 15-b ID Read
CS
Mode3
0 1 2 3 4 5 6 7 8
15 16
23 24
31 32
39
SCK
Mode0
8CL
SI
SO
ABh
X
High Impedance
X
X
3Eh
3Eh
MSB
MSB
No.A2096-13/22