Parallel_Boot
No
Yes
Initialize GP I/O MUX
and Dir registers
GPIO[9,8,5:0] = input
GPIO27 = input
GPIO26 = output
Valid
KeyValue
(0x08AA)
?
reserved words
Read and discard 8
Read EntryPoint
address
CopyData
Call
Return
EntryPoint
Enable pullups on
GPIO[9,8,5:0]
Return Flash EntryPoint
C-Boot ROM Description
655
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
ROM Code and Peripheral Booting
Figure 6-29. Parallel GPIO Mode Overview
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 device and the device 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 than the device.