Control Subsystem C28X Processor After Reset Flow; Vector Table Mapping After Reset Operation - Texas Instruments Concerto F28M35 Series Technical Reference Manual

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Vector MAPS
(2)
BROM Vector
(1)
On the 28x devices, the VMAP and M0M1MAP modes are set to 1 on reset. The ENPIE mode is forced to 0 on reset.
(2)
The reset vector is always fetched from the boot ROM.
After the reset and boot is complete, the PIE vector table should be initialized by the user's code. Then the
application enables the PIE vector table. From that point on the interrupt vectors are fetched from the PIE
vector table. Note: when a reset occurs, the reset vector is always fetched from the vector table as shown
in Table 1-11. After a reset the PIE vector table is always disabled.
which the vector table mapping is selected.
Figure 1-6. Control Subsystem C28x Processor After Reset Flow
Recommended flow for 280x applications
Reset
(power-on reset or warm reset)
PIE disabled (ENPIE=0)
VMAP = 1
OBJMODE = 0
AMODE = 0
MOM1MAP = 1
Yes
Reset vector fetched from
boot ROM
Branch into bootloader
routines, depending on the
state of GPIO pins
User code initializes:
OBJMODE and AMODE state
PIE enable (ENPIE = 1)
PIE vector table
PIEIERx registers
CPU IER register and INTM
Vectors (except for reset)
are fetched from PIE vector map
A The compatibility operating mode of the 28x CPU is determined by a combination of the OBJMODE and AMODE bits
in Status Register 1 (ST1):
Operating Mode
C28x Mode
24x/240xA Source-Compatible
C27x Object-Compatible
B The reset vector is always fetched from the boot ROM.
SPRUH22I – April 2012 – Revised November 2019
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Table 1-11. Vector Table Mapping After Reset Operation
Reset Fetched From Address Range
Boot ROM Block 0x3FFFC0 - 0x3FFFFF
Using
peripheral
interrupts
?
Yes
†
‡
Copyright © 2012–2019, Texas Instruments Incorporated
(1)
VMAP
1
Figure 1-6
Used for test purposes only
User code initializes:
OBJMODE and AMODE state1
CPU IER register and INTM
VMAP state
VMAP = 1
?
No
Vectors
(except for reset) are
fetched from BROM
vector map
OBJMODE
1
1
0
Exceptions and Interrupts Control
(1)
M0M1MAP ENPIE
1 0
illustrates the process by
Vectors
No
(except for reset)
are fetched
from M0 vector
‡
map
‡
AMODE
0
1
0 (Default at reset)
System Control and Interrupts
(1)
105