Functional Description
Table 26-12. NAND Timings Parameters (continued)
Parameter
Description
Value [clock cycles]
t
rddata
CE low to data latch time
21
t
OEoff
CE low to OE high time
24
t
WEoff
CE low to WE high time
22
and
describes the timings configured for NAND device access. The one clock
cycle is 20 ns, which correspond to 50-MHz frequency.
Device Detection and Parameters
The ROM Code first performs an initial wait for device auto initialization (with 250ms timeout) with polling
of the ready information. Then, it needs to identify the NAND type connected to the GPMC interface. The
GPMC is initialized using 8 bits, asynchronous mode. The NAND device is reset (command FFh) and its
status is polled until ready for operation (with 200ms timeout). The ONFI Read ID (command 90h /
address 20h) is sent to the NAND device. If it replies with the ONFI signature (4 bytes) then a Read
parameters page (command ECh) is sent. If the parameters page does not have the ONFI signature, then
the ONFI identification fails. If the ONFI identification passes, the information shown in
is then
extracted: page size, spare area size, number of pages per block, and the addressing mode. The
remaining data bytes from the parameters page stream are simply ignored.
Table 26-13. ONFI Parameters Page Description
Offset
Description
Size (bytes)
6
Features supported
2
80
Number of data bytes per page
4
84
Number of spare bytes per page
2
92
Number of pages per block
4
101
Number of address cycles
1
If the ONFI Read ID command fails (it will be the case with any device not supporting ONFI) then the
device is reset again with polling for device to be ready (with 200ms timeout). Then, the standard Read ID
(command 90h / address 00h) is sent. If the Device ID (2
nd
byte of the ID byte stream) is recognized as
being a supported device then the device parameters are extracted from an internal ROM Code table. The
list of supported devices is shown in
Table 26-14. Supported NAND Devices
Capacity
Device ID
Bus Width
Page size
512 Mb
F0
x8
2048
512 Mb
C0
x16
2048
512 Mb
A0
x8
2048
512 Mb
B0
x16
2048
512 Mb
F2
x8
2048
512 Mb
C2
x16
2048
512 Mb
A2
x8
2048
512 Mb
B2
x16
2048
1 Gb
F1
x8
2048
1 Gb
C1
x16
2048
1 Gb
A1
x8
2048
1 Gb
B1
x16
2048
2 Gb
DA
x8
2048
2 Gb
CA
x16
2048
2 Gb
AA
x8
2048
2 Gb
BA
x16
2048
4120Initialization
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated