C-Boot ROM Description
624
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
ROM Code and Peripheral Booting
Table 6-17. C-Boot ROM GPIO Assignments for Boot Modes
C-Boot ROM
Boot Mode
Peripheral
interface
Boot Function
Name for pin
Direction
GPIO(s) used
Pin Mux Assignment
Peripheral Mode
Core Select
SCI
SCIA
SCITXDA
Output
PF3_GPIO35
1
Control
Subsystem
SCIRXDA
Input
PF4_GPIO36
1
Control
Subsystem
I2C
I2CA
SDAA
Bi-Directional
PF0_GPIO32
1
Control
Subsystem
SCLA
Output
PF1_GPIO33
1
Control
Subsystem
SPI
SPIA
SPISIMOA
Output
PD0_GPIO16
1
Control
Subsystem
SPISOMIA
Input
PD1_GPIO17
1
Control
Subsystem
SPICLKA
Output
PD2_GPIO18
1
Control
Subsystem
SPISTEA
Output
PD3_GPIO19
1
Control
Subsystem
Parallel Boot
Mode
GPIO (s)
D0
Input
PA0_GPIO0
0(default)
Control
Subsystem
D1
Input
PA1_GPIO1
0(default)
Control
Subsystem
D2
Input
PA2_GPIO2
0(default)
Control
Subsystem
D3
Input
PA3_GPIO3
0(default)
Control
Subsystem
D4
Input
PA4_GPIO4
0(default)
Control
Subsystem
D5
Input
PA5_GPIO5
0(default)
Control
Subsystem
D6
Input
PB0_GPIO8
0(default)
Control
Subsystem
D7
Input
PB1_GPIO9
0(default)
Control
Subsystem
HOST_CTRL
Input
PE3_GPIO27
0(default)
Control
Subsystem
DSP_CTRL
Ouput
PE2_GPIO26
0(default)
Control
Subsystem
6.6.7 C-Boot ROM Clock Initializations
On these devices, M-Boot ROM configures the clock settings before bringing the control subsystem out of
reset. C-Boot ROM doesn’t configure any clock settings.
Please refer to
and the Clock Control section of the
System Control and Interrupts
chapter
for more details.
6.6.8 C-Boot ROM Functional Flow
As shown in the CPU vector table, InitBoot is the main function called whenever C-Boot ROM is executed
after a reset. This section explains the flow of C-Boot ROM function-by-function.
6.6.8.1
INITBOOT ()
•
Initialize the stack pointer
•
Put CPU in C28x Object Mode
•
Check the CRESC register and if the POR bit is set, then perform a RAM-INIT on all control subsystem