TS-4710 NVRAM: Difference between revisions
From embeddedTS Manuals
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The RTC has an included 128 byte NVRAM which can be accessed using tshwctl. | The RTC has an included 128-byte battery-backed NVRAM which can be accessed using tshwctl. Its contents will remain with the main power off, so long as the RTC battery is installed and withing a valid voltage range. | ||
<source lang=bash> | <source lang=bash> | ||
Revision as of 13:06, 16 December 2015
The RTC has an included 128-byte battery-backed NVRAM which can be accessed using tshwctl. Its contents will remain with the main power off, so long as the RTC battery is installed and withing a valid voltage range.
tshwctl --nvram
This will return a format such as:
nvram0=0xf7f8a73e nvram1=0x2fef5ae0 nvram2=0x48ca4278 ... nvram31=0x70544510
This breaks up the NVRAM into 32x 32-bit registers which can be accessed in bash. As this uses the name=value output, you can use "eval" for simple parsing:
eval `tshwctl --nvram`
echo $nvram2
From the above value, this would return 0x48ca4278. To set values, you can use environment variables:
nvram0=0x42 tshwctl --nvram
If you read back nvram0, this should now confirm the value is 0x42.