Flash Registers
508
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
Internal Memory
5.4
Flash Registers
The M3 flash/OTP memory and C28x flash can be configured by the registers shown in
and
, respectively. All the control subsystem flash registers are protected by the code security
module. For master subsystem flash registers, the SECZONEREQUEST semaphore register (mapped at
address 0x400FA160) is provided for accessing the flash registers for the two M3 security zones, with out
compromising on security.
The flash control registers should not be written to by code that is running from OTP or flash memory or
while an access to flash or OTP is in progress. All register accesses to the flash registers should be made
from code executing outside of flash/OTP memory; an access should not be attempted until all activity on
the flash/OTP has completed. No hardware is included to protect against this. To summarize, you can
read the flash registers from code executing in flash/OTP; however, do not write to the registers.
CPU write access to the flash registers can be enabled only by executing the EALLOW instruction on the
C28x core and by initializing MWRALLOW with 0xA5A5A5A5 on Cortex-M3. Write access to flash
registers is disabled when the EDIS instruction is executed on the C28x core. For Cortex-M3, write access
to flash registers is disabled when MWRALLOW is initialized with any value other than 0xA5A5A5A5. This
protects the registers from spurious accesses. The registers can be accessed through the JTAG port
without the need to execute EALLOW/initialize MWRALLOW.
Table 5-84. Flash Registers Memory Map on Master Subsystem
Register
Acronym
Register
Description
Size (x8)
Type
M3 Offset (0x8)
M3 Protection
Reset Source
Flash Control Registers
0x400F:A000
FRDCNTL
Flash Read
Control Register
4
R/W
0x0
MWRALLOW
M3SYSRSTn
FSPRD
Flash read
margin control
register
4
R/W
0x4
MWRALLOW
M3SYSRSTn
Reserved
Reserved
52
FBAC
Flash Bank
Access Control
Register
4
R/W
0x03C
MWRALLOW
M3SYSRSTn
FBFALLBACK
Flash Bank
Fallback Power
Register
4
R/W
0x040
MWRALLOW
M3SYSRSTn
FBPRDY
Flash Bank
Pump Ready
Register
4
R
0x044
MWRALLOW
M3SYSRSTn
FPAC1
Flash Pump
Access Control
Register 1
4
R/W
0x048
MWRALLOW
M3SYSRSTn
FPAC2
Flash Pump
Access Control
Register 2
4
R/W
0x04C
MWRALLOW
M3SYSRSTn
FMAC
Flash Module
Access Control
Register
4
R
0x050
MWRALLOW
M3SYSRSTn
FMSTAT
Flash Module
Status Register
(Used with Flash
API – Refer to
Flash Application
Programming
Interface User’s
Specification for
details of this
register)
4
R
0x054
MWRALLOW
M3SYSRSTn
Reserved
Reserved
264