Read sector
Program address
and interrupts registers
Issue load command
Read 512 bytes sector
Failed
Success
init-025
Interrupt register:
INT has occurred?
Status register:
Error
No
Yes
Yes
No
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Device Initialization by ROM Code
•
OneNAND/Flex-OneNAND detection and parameters
The ROM code identifies a OneNAND/Flex-OneNAND device by reading the its identification data.
There are two ways to read identification data: using serial commands and reading from fixed memory
mapped registers. The ROM code reads identification data using both methods and compares the
result. When the comparison passes, the ROM code assumes that the OneNAND/Flex-OneNAND
device is connected. If the booting device is successfully recognized, the ROM code reads the booting
device configuration (amount and size of data buffers) and configures it for asynchronous mode
(default).
26.4.7.5.2 OneNAND/Flex-OneNAND Read Sector Procedure
When booting requests a sector from the OneNAND/Flex-OneNAND device, the ROM code issues the
load operation, which transfers the content of the requested sector to the data buffer RAM. The ROM code
waits until the operation completes, polling the OneNAND/Flex-OneNAND interrupt register. The status
register is then checked and the ROM code returns FAIL if the operation completes with an error.
Otherwise, the data buffer RAM is copied to the destination buffer.
shows this procedure.
Figure 26-23. OneNAND/Flex-OneNAND Read Sector
3557
SWPU177N – December 2009 – Revised November 2010
Initialization
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