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GR716-DS-UM, May 2019, Version 1.29
507
www.cobham.com/gaisler
GR716
51.6
Boot source requirements
This chapter specifies limitations to external interface or components during boot.
51.6.1 SpaceWire Remote access
Remote access via SpaceWire (without software support) requires the SpaceWire input frequency to
be 5 MHz, 10 MHz, 20 MHz or 25 MHz.
51.6.2 External SPI Memory
External SPI memories will be clocked with system clock divided by 8 during the boot sequence. The
external SPI memory is assumed to support read command 0x3 and have 3 address bytes as default.
The external SPI memory interface is intended for devices using the above configuration, for example
the following devices:
•
AT69170E
•
AT17LV010
51.6.3 External I2C Memory
No direct boot from I2C memory. The Boot ROM only supports 10 bit device addressing on the I2C
bus. The external I2C memory is assumed to have 2 address bytes.
51.6.4 External PROM/SRAM memory
The access time for external PROM shall be equal or less than 16 system clock cycles and for external
SRAM the access time shall be equal or less than 4 system clock cycles.
51.6.5 NVRAM
Booting using the NVRAM memory controller is also supported by the ASIC design, please contact
[email protected] for more information about options for bare die.
51.7
Protection schemes
The boot image has a number of protection schemes build in to check for erroneous boot software,
hardware malfunction:
SRAM/PROM:
•
BCH EDAC protection
•
Scrubber (SRAM only)
•
ASW load image protection with CRC protection
•
Redundant ASW load image
•
Watchdog timer
SPI Memory:
•
BCH EDAC protection
•
ASW load image protection
•
Redundant ASW load image with CRC protection
•
Watchdog timer
I2C Memory:
•
ASW load image protection