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NXP Semiconductors
PNX15xx/952x Series
Volume 1 of 1
Chapter 6: Boot Module
PNX15XX_PNX952X_SER_N_4
NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 4.0 — 03 December 2007
6-205
The default state of the BOOT_MODE[3:0] pins may be determined by the internal
pull-ups and pull-downs presents in the I/Os of PNX15xx/952x Series. However the
BOOT_MODE[7:4] pins must be pulled up or down at board level to ensure a proper
boot function.
3
0x0
CAS_LATENCY DDR SDRAM devices support different types of CAS latencies.
However they do not support all the combinations. PNX15xx/952x
Series offers the possibility to program the MMI (and therefore the
DDR SDRAM devices) with the appropriate CAS latency at boot
time. This is crucial for standalone boot from Flash memories
devices since 8 Kilobytes of data is stored into the main memory
during the execution of the boot scripts.
0 - 2.5 clock periods
1 - 3 clocks periods
2
0x1
ROM_WIDTH/
IIC_FASTMODE
This pin has a dual functional mode:
If BOOT_MODE[1:0] = “00”, “01”, or “10” (Boot from Flash
memory)
0 - 8-bit data wide ROM
1 - 16-bit data wide ROM
If BOOT_MODE[1:0] = “11” (Boot from I2C EEPROM)
0 - 100 KHz
1 - 400 KHz
1:0
0x3
BOOT_MODE
The main boot mode is determined as follows:
00 - Set up the system and start the TM3260 CPU from a 8- or 16-
bit NOR Flash memory or ROM attached to the PCI-XIO bus.
01 - Set up the system and start the TM3260 CPU from a 8- or 16-
bit NAND Flash memory or ROM attached to the PCI-XIO bus.
10 - Set up the PNX15xx/952x Series system in host-assisted
mode and allow the host CPU to nish the conguration of the
PNX15xx/952x Series system and start the TM3260 CPU.
11 - Boot from an I2C EEPROM attached to the I2C interface.
EEPROMs of 2 to 64 Kilobytes are supported. The entire system
can be initialized in a custom fashion by the boot commands
contained in the EEPROM. This mode can be used for standalone
or host-assisted boot mode when the other internal boot scripts
are not meeting the specic requirements of the application. In
this mode the boot script is in the EEPROM. Refer to
Section 2.3for further details on the EEPROM content.
Table 1: The Boot Modes …Continued
BOOT_MODE
Bits
GPIO
pins
Default
Function
Description