EW31244SL7QV Datasheet, PDF (42/252 Pages) Intel Corporation – Intel® 31244 PCI-X to Serial ATA Controller

Intel^® 31244 PCI-X to Serial ATA Controller
Serial EEPROM
3.1.8 Read ID Register (RDID) Command
Figure 13.
The RDID command allows the user to read the manufacturer and product ID of the EEPROM.
The first byte after the command will be the manufacturer code (e.g., 1Fh = Atmel*), followed by
the device code. The read ID register (RDID) operation is shown in Figure 13.
Read ID Register (RDID) Operation
SCS#
SCLK
0 1 2 3 4 5 6 7 ^{8 9 10 11 12 13 14 15} 16 17 18 19 20 21 22
SDO ^{0 0 0 0 0 0 0 1}
SDI
Hi -Z
Hi -Z
7 6 5 4 3 2 1 07 6 5 4 3 2 1 0
Manufacturer ID
Device ID
The RDID command may only be issued when the EEPROM is ready to accept a new command.
When the device is busy, it cannot accept any new commands except RDSR. To issue a RDID
command:
1. Issue a RDSR command to read that the RDY# bit is LOW in the EEPROM’s Status Register
to ensure that the EEPROM is ready to receive a new command.
2. When RDY# is not LOW, continue issuing RDSR commands until RDY# becomes LOW.
3. Issue the RDID command with an 8-bit write of 15h to the SPI Command Register at offset
90h.
4. Upon completion of the RDID command, the 8-bit Manufacturer’s ID (1Fh for Atmel) will be
located in bits 7:0 of the SPI Data Register (offset 94h) and the 8-bit Device ID (060h for
AT25F1024) will be located in bits 15:8 of the SPI Data Register (offset 94h).
42
April 2004
Developer’s Manual