Datasheet

TMS320C28346, TMS320C28345, TMS320C28344
TMS320C28343, TMS320C28342, TMS320C28341
SPRS516D –MARCH 2009–REVISED AUGUST 2012 www.ti.com
3.2.8 Boot ROM
The Boot ROM is factory-programmed with boot-loading software. Boot-mode signals are provided to tell
the bootloader software what boot mode to use on power up. The user can select to boot normally or to
download new software from an external connection or to select boot software that is programmed in the
internal ROM. The Boot ROM also contains standard tables, such as SIN/COS waveforms, for use in math
related algorithms.
Table 3-2. Boot Mode Selection
MODE GPIO87/XA15 GPIO86/XA14 GPIO85/XA13 GPIO84/XA12 MODE
(1)
F 1 1 1 1 Secure boot
(2)
E 1 1 1 0 SCI-A boot
D 1 1 0 1 SPI-A boot
C 1 1 0 0 I2C-A boot Timing 1
B 1 0 1 1 eCAN-A boot Timing 1
A 1 0 1 0 McBSP-A boot
9 1 0 0 1 Jump to XINTF x16
8 1 0 0 0 Reserved
7 0 1 1 1 eCAN-A boot Timing 2
6 0 1 1 0 Parallel GPIO I/O boot
5 0 1 0 1 Parallel XINTF boot
4 0 1 0 0 Jump to SARAM
3 0 0 1 1 Branch to check boot mode
2 0 0 1 0 I2C-A boot Timing 2
1 0 0 0 1 Reserved
0 0 0 0 0 TI Test Only
(1) All four GPIO pins have an internal pullup.
(2) This mode is available on secure devices only. See Section 3.2.9, Security.
3.2.9 Security
The 128-bit password locations on these devices will always read back 0xFFFF. To preserve compatibility
with other C28x designs with code security, the password locations at 0x33FFF8–0x33FFFF must be read
after a device reset; otherwise, certain memory locations will be inaccessible. The Boot ROM code
performs this read during startup. If during debug the Boot ROM is bypassed, then it is the responsibility of
the application software to read the password locations after a reset.
Custom Encryption: Activating the Code Security Module (CSM) and Emulation Code Security
Logic (ECSL)
Custom secure versions of these devices are available which enable the CSM and ECSL logic on these
devices. In the custom version, the 128-bit password locations are set to a customer-chosen value,
activating the Code Security Module (CSM), which protects the Hx RAM memories from unauthorized
access. Additionally, a TI-generated AES decryption routine is embedded into an on-chip secure ROM,
providing a method to secure application code that is stored externally. Contact TI at [e-mail] for
more details.
42 Functional Overview Copyright © 2009–2012, Texas Instruments Incorporated
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TMS320C28341