loading image from external memory, getting prop to run it

Bill Henning

Ok, I tried search.parallax.com, but I could not find how to get the propeller to reset and run something I might load into it under the control of a large memory model loader [noparse]:)[/noparse]

Basically, I need to do a warm boot of the chip so that it will execute the image I load into the hub memory.

I have a vague memory that Chip posted how to do this over a year ago, but I could not find it.

A link would be most appreciated

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Mike Green

Don't have the link, but here's the assembly code:

'
' Start up oscillator and begin Spin program at $0010
' (assumes EEPROM data already loaded into $0000-$7FFF)
' (assumes currently running RCFAST oscillator)
' (assumes this is COG 0 - gets rebooted)
'
              rdbyte  address,#$0004          'if xtal/pll enabled, start up now
              and      address,#$F8             '..while remaining in rcfast mode
              clkset  address
:delay     djnz     time_xtal,#:delay       'allow 20ms @20MHz for xtal/pll to settle
              rdbyte  address,#$0004           'switch to selected clock
              clkset  address
              coginit interpreter              'reboot cog with interpreter

time_xtal       long    20 * 20000 / 4 / 1      '20ms (@20MHz, 1 inst/loop)
interpreter     long    $0001 << 18 + $3C01 << 4 + %0000
address          res     1

This is used in the various FemtoBasic versions and the Propeller OS.

Bill Henning

Thanks Mike - you've got my vote for most helpful guy on the forums [noparse]:)[/noparse]

Mike Green said...
Don't have the link, but here's the assembly code:

'
' Start up oscillator and begin Spin program at $0010
' (assumes EEPROM data already loaded into $0000-$7FFF)
' (assumes currently running RCFAST oscillator)
' (assumes this is COG 0 - gets rebooted)
'
              rdbyte  address,#$0004          'if xtal/pll enabled, start up now
              and      address,#$F8             '..while remaining in rcfast mode
              clkset  address
:delay     djnz     time_xtal,#:delay       'allow 20ms @20MHz for xtal/pll to settle
              rdbyte  address,#$0004           'switch to selected clock
              clkset  address
              coginit interpreter              'reboot cog with interpreter

time_xtal       long    20 * 20000 / 4 / 1      '20ms (@20MHz, 1 inst/loop)
interpreter     long    $0001 << 18 + $3C01 << 4 + %0000
address          res     1

This is used in the various FemtoBasic versions and the Propeller OS.

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www.mikronauts.com - a new blog about microcontrollers