Cirrus Logic CS485xx - Manual (Page 28)

Softboot
CS485xxr Hardware User’s Manual
DS734UM7 Copyright 2009 Cirrus Logic, Inc. 2-10
Figure 2-5. Soft Boot Example Flowchart
2.5.2.2.1 Softboot Example Procedure
1. Send the SOFTBOOT message. The host sends the SOFTBOOT message to the CS485xx to begin
overlay swap.
2. Wait for IRQ low. The host then waits for SCP_IRQ to go low. If the TIMEOUT period has been
reached, the host should exit. If the IRQ pin is LOW, proceed to step 3.
MSG
==BOOT_START
WRITE_* (SLAVE_BOOT)
READ_* (MSG)
N
Y
MSG==
BOOT_SUCCESS
N
Y
READ_* (MSG)
MSG ==APP_START
WRITE_* (SOFT_RESET)
READ_* (MSG)
N
Y
MORE .ULD FILES?
Y
N
DONE
SEND HARDWARE
CONFIGURATIONS
SEND FIRMWARE
CONFIGURATIONS
WRITE_* (KICKSTART)
* is replaced with SPI,
I2C, etc. depending on
the communication
protocol used.
EXIT(ERROR)
EXIT(ERROR)
EXIT(ERROR)
MSG == SOFTBOOT_ACK?
WRITE_* (SOFTBOOT)
READ_* (MSG) EXIT(ERROR)
N
Y
START
IRQ == LOW?
N
Y Y
N
TIMEOUT?
SEND .ULD FILE