Cirrus Logic CS485xx - Manual (Page 24)

Slave Boot Procedures
CS485xxr Hardware User’s Manual
DS734UM7 Copyright 2009 Cirrus Logic, Inc. 2-6
2.3.3 Boot Messages
The Slave Boot procedure uses a number of messages to configure and synchronize the boot process.
Please use the messages listed below when implementing the boot process as a part of the system host
controller firmware.
2.3.3.1 Slave Boot
The SLAVE_BOOT message is used when the system host controller will send each.uld file directly to the
CS485xx . The SLAVE_BOOT message must be issued for each overlay image (.uld file) that is downloaded
to the CS485xx . Please see Figure 2-2 for more details.
2.3.3.2 Soft Reset
The SOFT_RESET message is the message sent to the CS485xx after all of the overlays have been
successfully booted. The SOFT_RESET leaves execution of the bootloader and begins execution of the
loaded overlays. The overlays can be configured once the SOFT_RESET message has been sent.
2.3.3.3 Messages Read from CS485xx
Table 2-4 defines the boot read messages, in mnemonic and actual hex value, used in CS485xx boot
sequences. Note that there is a unique {ID} for every.uld file.
Table 2-2. SLAVE_BOOT message for CS485xx
MNEMONIC VALUE
SLAVE_BOOT 0x80000000
Table 2-3. SOFT_RESET message for CS485xx
MNEMONIC VALUE
SOFT_RESET 0x40000000
Table 2-4. Boot Read Messages from CS485xx
MNEMONIC VALUE
BOOT_START 0x00000001
BOOT_SUCCESS 0x00000002
APP_START 0x00000004
BOOT_ERROR_CHECKSUM 0x000000FF
INVALID_BOOT_TYPE 0x000000FE
BOOT_FAILURE 0x000000F8
APPLICATION_FAILURE 0xF0{ID}0000