Overview Of Parallel Gpio Bootloader Operation - Texas Instruments Concerto F28M36 Series Technical Reference Manual

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6.5.15.4 M-Boot ROM Parallel IO Boot Mode
This section gives details on the Parallel IO boot mode in M-Boot ROM on these devices.
6.5.15.4.1 M-Boot ROM Parallel Boot Mode IO Configuration
Below are the IOs used in parallel boot mode.
D0- PA0_GPIO0, GPIO mode
D1- PA1_GPIO1, GPIO mode
D2- PA2_GPIO2, GPIO mode
D3- PA3_GPIO3, GPIO mode
D4- PA4_GPIO4, GPIO mode
D5- PA5_GPIO5, GPIO mode
D6- PB0_GPIO8, GPIO mode
D7- PB1_GPIO9, GPIO mode
HOST_CTRL – PE3_GPIO27, GPIO mode
DSP_CTRL – PE2_GPIO26, GPIO mode
6.5.15.4.2 M-Boot ROM Parallel Boot Mode Protocol
The parallel general purpose I/O (GPIO) boot mode asynchronously transfers code from GPIO0 -GPIO5,
GPIO8-GPIO9 to internal memory. Each value is 8 bits long and follows the same data flow as outlined in
Section 6.6.15.1. The exception is that the C2000 hex utility hex file generated for the master subsystem
boot has the least significant byte (LSB) and the most significant byte (MSB) swapped when compared to
the hex file generated for the control subsystem boot. The rest of the concepts for data format and data
flow are similar between the master subsystem and control subsystem.
Figure 6-5. Overview of Parallel GPIO Bootloader Operation
The master subsystem communicates with the external host device by polling/driving the GPIO27 and
GPIO26 lines. The handshake protocol shown in
word via GPIO [9,8,5:0]. This protocol is very robust and allows for a slower or faster host to communicate
with the master subsystem.
Two consecutive 8-bit words are read to form a single 16-bit word. The most significant byte (MSB) is read
first followed by the least significant byte (LSB). In this case, data is read from GPIO[9,8,5:0].
The 8-bit data stream is shown in
SPRUHE8E – October 2012 – Revised November 2019
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Figure 6-6
Table 6-10.
Copyright © 2012–2019, Texas Instruments Incorporated
M-Boot ROM Description
must be used to successfully transfer each
ROM Code and Peripheral Booting
607