SYS Registers
77
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
System Resets, Interrupts, and Operating Modes, System Control Module
(SYS)
1.16.1 SYSCTL Register
SYS Control Register
Figure 1-10. SYSCTL Register
15
14
13
12
11
10
9
8
Reserved
r0
r0
r0
r0
r0
r0
r0
r0
7
6
5
4
3
2
1
0
Reserved
SYSJTAGPIN
SYSBSLIND
Reserved
SYSPMMPE
Reserved
SYSRIVECT
r0
r0
rw-[0]
r-0
r0
rw-[0]
r0
rw-[0]
Table 1-17. SYSCTL Register Description
Bit
Field
Type
Reset
Description
15-8
Reserved
R
0h
Reserved. Always reads as 0.
7-6
Reserved
R
0h
Reserved. Always reads as 0.
5
SYSJTAGPIN
RW
0h
Dedicated JTAG pins enable. Setting this bit disables the shared functionality of
the JTAG pins and permanently enables the JTAG function. This bit can only be
set once. Once it is set it remains set until a BOR occurs.
0b = Shared JTAG pins (JTAG mode selectable using SBW sequence)
1b = Dedicated JTAG pins (explicit 4-wire JTAG mode selection)
4
SYSBSLIND
R
0h
BSL entry indication. This bit indicates a BSL entry sequence detected on the
Spy-Bi-Wire pins.
0b = No BSL entry sequence detected
1b = BSL entry sequence detected
3
Reserved
R
0h
Reserved. Always reads as 0.
2
SYSPMMPE
RW
0h
PMM access protect. This controls the accessibility of the PMM control registers.
Once set to 1, it only can be cleared by a BOR.
0b = Access from anywhere in memory
1b = Access only from the BSL segments
1
Reserved
R
0h
Reserved. Always reads as 0.
0
SYSRIVECT
RW
0h
RAM-based interrupt vectors
0b = Interrupt vectors generated with end address TOP of lower 64K FRAM
FFFFh
1b = Interrupt vectors generated with end address TOP of RAM, when RAM
available.
Note: On devices that contain RAM, it is possible to use the RAM as an alternate
location for the interrupt vector locations. Setting the SYSRIVECT bit to '1' in
SYSCTL causes the interrupt vectors to be remapped to the top of RAM. The
total RAM size varies depending on the device configurations and could include
one or multiple RAM sections. The alternate location is always the highest
address of the entire RAM space available in the device. Note that the
SYSRIVECT bit is automatically cleared on a BOR, so the default reset vector
location (0FFFEh) will be used after a BOR before setting the SYSRIVECT bit to
'1'. On devices with LEA, the highest RAM address may be part of the LEA
shared RAM. Care must be taken to avoid address conflicts if LEA is used in this
case.