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1.
Introduction
Before a PNX15xx/952x Series system can begin operating, there are a couple of
main PNX15xx/952x Series interfaces like the main memory interface (MMI) or the
PCI that require to be congured. Since the TM3260 cannot begin operating before
these registers and circuits are initialized, the TM3260 cannot be relied on to initialize
these resources. Consequently, PNX15xx/952x Series needs an independent
bootstrap facility for low-level initialization: the Boot module.
The boot module provides boot scripts to reduce the board system cost.
UNFORTUNATELY THESE INTERNAL BOOTSCRIPTS CANNOT BE USED IN
CURRENT PNX15xx/952x Series. The scripts allow support for both host-assisted
mode, and standalone boot mode. The supported four boot modes are:
Boot from an external EEPROM attached on the I2C bus interface. The EEPROM
contains a list of MMIO registers and memory locations to be written.
Boot for host-assisted systems. The host CPU kicks off TM3260. Therefore the
host is in charge of downloading the TM3260 binary program and in charge of
setting properly the remaining of the system.
Boot from NAND or NOR Flash memory devices. The rst 8 Kilobytes of the
Flash memory contains the bootstrapping program for TM3260. The Flash
memory can be 8- or 16-bit wide.
The different modes are determined by the GPIO[11:8,3:0]/BOOT_MODE[7:0] pins.
Once the boot procedure is complete, the boot module goes to sleep until another
2.
Functional Description
The PNX15xx/952x Series boot sequence begins with the assertion of the system
reset. The system reset is seen by the boot module through the internal signal
peri_rst_n. After this internal reset is de-asserted only the system boot block and the
PCI interfaces are allowed to operate. In particular, the TM3260 remains in the reset
state until it is explicitly released from reset during or after the boot procedure. In the
standalone boot mode the system boot module is responsible for releasing the
TM3260 from the reset state. In host-assisted boot the boot logic releases the
PNX15xx/952x Series system from reset such that the PNX15xx/952x Series
Chapter 6: Boot Module
PNX15xx/952x Series Data Book – Volume 1 of 1
Rev. 4.0 — 03 December 2007
Product data sheet