Texas Instruments TMS320C6454 - Manual (Page 13)

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PRODUCT PREVIEW
2.4.2 2nd-Level Bootloaders
TMS320C6454
Fixed-Point Digital Signal Processor
SPRS311A – APRIL 2006 – REVISED DECEMBER 2006
such as Code Composer Studio.
For the PCI host boot, the CPU is out of reset, but it executes an IDLE instruction until a DSP interrupt
is generated by the host. The host can generate a DSP interrupt through the PCI peripheral by setting
the DSPINT bit in the Back-End Application Interrupt Enable Set Register (PCIBINTSET) and the
Status Set Register (PCISTATSET).
Note that the HPI host boot is a hardware boot mode while the PCI host boot is a software boot mode.
If PCI boot is selected, the on-chip bootloader configures the PLL1 Controller such that CLKIN1 is
multiplied by 15. More specifically, PLLM is set to 0Eh (x15) and RATIO is set to 0 (÷1) in the PLL1
Multiplier Control Register (PLLM) and PLL1 Pre-Divider Register (PREDIV), respectively. The CLKIN1
frequency must not be greater than 50 MHz so that the maximum speed of the internal ROM, 750
MHz, is not violated. The CFGGP[2:0] pins must be set to 000b during reset for proper operation of the
PCI boot mode.
As mentioned previously, a DSP interrupt must be generated at the end of the host boot process to
begin execution of the loaded application. Since the DSP interrupt generated by the HPI and PCI is
mapped to the EDMA event DSP_EVT (DMA channel 0), it will get recorded in bit 0 of the EDMA
Event Register (ER). This event must be cleared by software before triggering transfers on DMA
channel 0.
•
EMIFA 8-bit ROM boot (BOOTMODE[3:0] = 0100b)
After reset, the device will begin executing software out of an Asynchronous 8-bit ROM located in
EMIFA CE3 space using the default settings in the EMIFA registers. This boot mode is a hardware
boot mode.
•
Master I2C boot (BOOTMODE[3:0] = 0101b)
After reset, the DSP can act as a master to the I2C bus and copy data from an I2C EEPROM or a
device acting as an I2C slave to the DSP using a predefined boot table format. The destination
address and length are contained within the boot table. This boot mode is a software boot mode.
•
Slave I2C boot (BOOTMODE[3:0] = 0110b)
A Slave I2C boot is also implemented, which programs the DSP as an I2C Slave and simply waits for a
Master to send data using a standard boot table format.
Using the Slave I2C boot, a single DSP or a device acting as an I2C Master can simultaneously boot
multiple slave DSPs connected to the same I2C bus. Note that the Master DSP may require booting
via an I2C EEPROM before acting as a Master and booting other DSPs.
The Slave I2C boot is a software boot mode.
Any of the boot modes can be used to download a 2nd-level bootloader. A 2nd-level bootloader allows for
any level of customization to current boot methods as well as definition of a completely customized boot.
TI offers a few 2nd-level bootloaders, such as an EMAC bootloader, which can be loaded using the
Master I2C boot.
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