TMS320LF2407A_17 Datasheet, PDF (43/134 Pages) Texas Instruments – DSP CONTROLLERS

TMS320LF2407A, TMS320LF2406A, TMS320LF2403A, TMS320LF2402A
TMS320LC2406A, TMS320LC2404A, TMS320LC2403A, TMS320LC2402A
DSP CONTROLLERS
SPRS145L − JULY 2000 − REVISED SEPTEMBER 2007
boot ROM (LF240xA only)
Boot ROM is a 256-word ROM memory-mapped in program space 0000−00FF. This ROM will be enabled if the
BOOT_EN pin is low during reset. The BOOT_EN bit (bit 3 of the SCSR2 register) will be set to 0 if the BOOT_EN
pin is low at reset. Boot ROM can also be enabled by writing 0 to the SCSR2.3 bit and disabled by writing 1 to
this bit.
The boot ROM has a generic bootloader to transfer code through SCI or SPI ports. The incoming code should
disable the BOOT_ROM bit by writing 1 to bit 3 of the SCSR2 register, or else, the whole Flash array will not
be enabled.
The boot ROM code sets the PLL to x2 or x4 option based on the condition of the SCITXD pin during reset. The
SCITXD pin should be pulled high/low to select the PLL multiplication factor. The choices made are as follows:
D If the SCITXD pin is pulled low, the PLL multiplier is set to 2.
D If the SCITXD pin is pulled high, the PLL multiplier is set to 4. (Default)
D If the SCITXD pin is not driven at reset, the internal pullup selects the default multiplier of 4.
Care should be taken such that a combination of CLKIN and the PLL multiplication factor should not result in
a CPU clock speed of greater than 40 MHz, the maximum rated speed.
Furthermore, when the bootloader is used, only specific values of CLKIN would result in a baud-lock for the SCI.
See the TMS320LF/LC240xA DSP Controllers Reference Guide: System and Peripherals (literature number
SPRU357) for more details about the bootloader operation.
flash/ROM security
240xA devices incorporate a security feature that prevents external access to program memory. This feature
is useful in preventing unauthorized duplication of proprietary code.
If access to Flash/ROM contents are desired for debugging purposes, two actions need to be taken:
1. A “dummy” read of locations 40h, 41h, 42h and 43h (of program memory space) is necessary. The word
“dummy” indicates that the destination address of this read is insignificant.
NOTE: Step 2 is not required if 40h−43h contain 0000 0000 0000 0000h or FFFF FFFF FFFF FFFFh.
2. A 64-bit password (split as four 16-bit words) must be written to the data-memory locations 77F0h, 77F1h,
77F2h, and 77F3h. The four 16-bit words written to these locations must match the four words stored in 40h,
41h, 42h, and 43h (of program memory space), respectively. The device becomes “unsecured” one cycle
after the last instruction that unsecures the part.
Code Security Module Disclaimer
The Code Security Module (“CSM”) included on this device was designed to password
protect the data stored in the associated memory (either ROM or Flash) and is warranted
by Texas Instruments (TI), in accordance with its standard terms and conditions, to
conform to TI’s published specifications for the warranty period applicable for this device.
TI DOES NOT, HOWEVER, WARRANT OR REPRESENT THAT THE CSM CANNOT BE
COMPROMISED OR BREACHED OR THAT THE DATA STORED IN THE
ASSOCIATED MEMORY CANNOT BE ACCESSED THROUGH OTHER MEANS.
MOREOVER, EXCEPT AS SET FORTH ABOVE, TI MAKES NO WARRANTIES OR
REPRESENTATIONS CONCERNING THE CSM OR OPERATION OF THIS DEVICE,
INCLUDING ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR
A PARTICULAR PURPOSE.
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