XINTF_Parallel_Boot
InitializeGPIOMUX
forx16XINTF
onzone6
GPIO13=input
GPIO12=output
Configuredefault
timingforXINTF
zone6
Readkeyvalueto
determineDataSize
andassignappropriate
GetWordDatafunction
Valid
KeyValue
(0x08AA or
0x10AA)
?
No
Yes
EnableWatchdog
andforcereset
ReadPLLCRand
DIVSEL values
ReadXINTFzone6
timingvalues
ConfigurePLL
ConfigureXINTF
Readremaining
reservedwords
ReadEntryPoint
address
Call
CopyData
ReturnEntryPoint
Bootloader Features
www.ti.com
200
SPRUI07–March 2020
Submit Documentation Feedback
Copyright © 2020, Texas Instruments Incorporated
Boot ROM
Figure 2-26. XINTF Parallel Mode Overview
Figure 2-27 shows the transfer flow from the host side. The operating speed of the CPU and host are not
critical in this mode as the host will wait for the 28x and the 28x will in turn wait for the host. In this manner
the protocol will work with both a host running faster and a host running slower then the 28x device.