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Table 27. Reset sequence (continued)
Controller
Step
Action
Description
2
Wait for reset clear.
Wait for reset assertion to be released. The reset
sequencer will stall as long as any of the following reset
inputs is asserted:
• CWJTAG_RST_B
• SW_RST_B
3
Sample switches.
Internal registers are reset to default values.
Registers that default to switch values are set now.
4
Drive configuration values.
Reset-sampled configuration signals are driven:
• CFG_RCW_SRC[3:0]
• CFG_SVR[0:1]
• CFG_ENG_USE[0]
Static (constant) configuration signals are driven:
• CFG_XSPI_MAP[0:3]
• CFG_MUX_I2C2
• CFG_MUX_I2C3
• CFG_MEM_WP
• CFG_MUX_UART2_SEL0
• CFG_MUX_uBUS1_UART_B
• CFG_MUX_uBUS2_UART_B
• CFG_MUX_uBUS1_SPI_B
• CFG_MUX_uBUS2_SPI_B
• CFG_MUX_uBUS1_PWM_B
• CFG_MUX_uBUS2_PWM_B
5
Release resets.
Release all resets shown in reset sequencer step 1.
The processor samples reset pins at this time.
6
Tristate reset-sampled pins.
A fixed time period after step 5:
Tristate configuration signals drive outputs.
This ensures proper configuration hold time.
The CPLD is no longer involved in reset activity.
Table continues on the next page...
System controller
QorIQ LS1028A Reference Design Board Reference Manual, Rev. b, 11/2018
NXP Semiconductors
COMPANY CONFIDENTIAL
49
Содержание QorIQ LS1028A
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