PNX17XX Datasheet, PDF (220/832 Pages) NXP Semiconductors – Connected Media Processor

Philips Semiconductors
Volume 1 of 1
PNX17xx Series
Chapter 6: Boot Module
Table 10: Examples of I²C EEPROM Devices
Size
Device
Write Protection
Coverage
16 kilobytes ATMEL 24C128
Full Array
32 kilobytes ATMEL 24C256
Full Array
64 kilobytes ATMEL 24C512
Full Array
Address Protocol
2 bytes
2 bytes
2 bytes
Comment
Tested
4.2 The Boot Commands and The Endian Mode
When writing to an MMIO register address, there is no endian mode issue. The msbit
of the word ‘V’ (Table 2) end up as the msbit of the MMIO register. When writing to an
SDRAM address there is an endian mode issue. Depending on the current endian
mode (Section 4. on page 3-8), 32-bit words get written to memory through the DCS
DRAM gate (Section 2.3 on page 3-4) in one of these two ways:
• In little-endian mode, the MSB of ‘V’ (or the last read EEPROM byte of the word),
end up in memory byte address ‘A+3’ and LSB (or first read EEPROM byte), end
up at the byte address ‘a’.
• In big-endian mode, the MSB of ‘V’ (or last read EEPROM byte), end up at the
byte address ‘A’ and the LSB (or first read EEPROM byte), end up at the byte
address ‘A+3’.
4.3 Details on I²C Operation
To retrieve the boot script, the Boot module performs the following I²C transactions:
• START, 10100000, wait-for-ack, 00000000, wait-for-ack, 00000000, wait-for-ack,
STOP
• START, 10100001, wait-for-ack, <accept data byte, send ACK or STOP if done>.
The interpretation of this sequence by 2048 bytes or smaller EEPROMs is:
• Write a byte value 0 to address 0 (setting the next address-pointer to byte
address 1).
• Read, starting from address 1.
Hence, for a 2048-byte or smaller EEPROM, the boot image must start at byte 1.
The interpretation of this sequence by 4096 bytes or larger EEPROMs is:
• Write a 0 byte-long sequence to address 0 (setting next address pointer to byte
address 0).
• Read, starting from address 0.
Hence, for a 4096-byte or larger EEPROM, the boot image must start at byte 0.
PNX17XX_SER_1
Preliminary data sheet
Rev. 1 — 17 March 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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