Kontron AM4904, User Manual

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Operating the Unit
80 AM4904 User Guide
www.kontron.com
FRU Product Info Area
• Product manufacturer: Kontron
• Product Name: AM4904-Base
• Product Part Number: 1028-5229
• Product Version: 1
• Product Serial Number: xxxxxxxxxx
• Asset Tag: 0
• FRU File ID: FRU-S1100-FABRIC-BASE-1P0
3.6 Bootloader
On the AM4904 board, the bootloader ‘u-boot‘ (universal bootloader) is used. The bootloader initializes the
main components of the board like CPU, SDRAM, serial lines etc. for operation. After this, kernel and appli-
cation are started from flash.
3.6.1 Power On Self Test
Upon power on or system reset, the bootloader performs a set of Power On Self Tests (POST) to check the
integrity of specific components. Components where a POST is available are:
• SDRAM
• PPC405 serial line
• PPC405 I2C
• PPC405 FE
In the case that a POST fails, a POST error code is written into the postcode high byte register of the onboard
CPLD. The boot process is not stopped as there are good chances the board can boot even in case of POST
errors. The postcode high byte register is also accessible by the PM which can report error codes to a sepa-
rate management instance. Thus more comprehensive diagnostic tests could be started.
The following table shows a list of available POST routines including POST error codes.
Table 3-36: POST Routines and Error Codes
Device Test
POST Numeri-
cal Error Code
POST Error Code
SDRAM Data bus - walking 1 test 0x20 PCW_DLINE
SDRAM Address bus - walking 1 test 0x40 PCW_ALINE
SDRAM Memory - read/write test 0x80 PCW_MEM
PPC405 UART Serial loopback teststring 0x01 PCW_SERIAL
PPC405 I2C Bus scan for devices from I2C_ADDR_LIST 0x02 PCW_I2C
PPC405 FE Phy access 0x08 PCW_ETH1
PPC405 FE Phy loopback test using special Ethernet test frame 0x10 PCW_ETH2
KCS KCS READY signal test 0x04 KCSCTL