2012年8月14日星期二

TMS320 Boot ROM

TMS320 Boot ROM

The Boot ROM is factory-programmed with boot-loading software. The Boot ROM program executes after
device reset and checks several GPIO pins to determine which boot mode to enter. For example, the user
can select to execute code already present in the internal Flash or download new software to internal
RAM through one of several serial ports. Other boot modes exist as well. The Boot ROM also contains
standard tables, such as SIN/COS waveforms, for use in math-related algorithms. Table 3-4 shows the
details of how various boot modes may be invoked. See the TMS320x281x DSP Boot ROM Reference
Guide (literature number SPRU095), for more information.
Table 3-4. Boot Mode Selection(1) (2)
BOOT MODE SELECTED GPIOF4 GPIOF12 GPIOF3 GPIOF2 (SCITXDA) (MDXA) (SPISTEA) (SPICLK)
GPIO PU status(3) PU No PU No PU No PU
Jump to Flash/ROM address 0x3F 7FF6.
A branch instruction must have been programmed here prior to 1 x x x
reset to re-direct code execution as desired.
Call SPI_Boot to load from an external serial SPI EEPROM 0 1 x x
Call SCI_Boot to load from SCI-A 0 0 1 1
Jump to H0 SARAM address 0x3F 8000 0 0 1 0
Jump to OTP address 0x3D 7800 0 0 0 1
Call Parallel_Boot to load from GPIO Port B 0 0 0 0
(1) Extra care must be taken due to any effect toggling SPICLK to select a boot mode may have on external logic.
(2) If the boot mode selected is Flash, H0, or OTP, then no external code is loaded by the bootloader.
(3) PU = pin has an internal pullup. No PU = pin does not have an internal pullup.

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