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Booting
21.5 Booting
21.5.1 Overview
Figure 21-6
shows the booting procedure. First, a booting device list is created. The list consists of all
devices which will be searched for a booting image. The list is filled in based on the SYSBOOT.
Once the booting device list is set up, the booting routine examines the devices enumerated in the list
sequentially and either executes the memory booting or peripheral booting procedure depending on the
booting device type. The memory booting procedure is executed when the booting device type is one of
NOR, NAND, or SPI-EEPROM. The peripheral booting is executed when the booting device type is
Ethernet, PCIe or UART.
The memory booting procedure reads data from a memory type device. If a valid booting image is
found and successfully read from the external memory device:
•
If a GP device, the Initial SW is simply started.
The peripheral booting procedure downloads data from a host (commonly a PC) to the device by
means of Ethernet, PCIe or UART links. The ROM Code uses a host-slave logical protocol for
synchronization. Upon successful PCIe enumeration (or UART or Ethernet connection) the host sends
the image binary contents. The peripheral booting procedure is described in detail in
If the memory or peripheral booting fails for all devices enumerated in the device list, then the ROM
Code gets back to the first device in the list. The device list is then processed again in a loop. This loop
shall be further interrupted by the MPU or secure watchdog.
Process Next Device
Device is of Memory Type
Jump to Initial SW
Get Next Device
in the List
1996
ROM Code Memory and Peripheral Booting
Preliminary
Figure 21-6. . ROM Code Booting Procedure
Set the Booting Device List Based
on the SW Booting Configuration
or SYSBOOT Pins
Process Device
Success
Memory
Booting
Fail
No
Last Device in the List?
© 2011, Texas Instruments Incorporated
Booting
Device is of Peripheral Type
Success
Peripheral
Booting
- Fail ,
- Timeout
Yes
No More Devices in the List
www.ti.com
Section
21.8.
Jump to Flash
Loader SW
SPRUGX9 – 15 April 2011
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