memory addressing in assembly

Neighborhood Physicist

I have the following

VAR
· long· I2C_Data[noparse][[/noparse]2]
OBJ
· I2CObject : "I2CAssemblyObject"
PUB main
' Initialize the I2C_Data to 0
· I2C_Data[noparse][[/noparse]0] := $0
· I2C_Data[noparse][[/noparse]1] := $0
· I2CObject.Start(@I2C_Data)

Inside the assembly I2C code I want to check both elements in the puesdo array.·

How do I get access to the second element?

·· RDLONG I2CData, PAR ' Gives access to the first element

Thanks.

Baggers

use something like this

'
'
'
    mov    ptr,PAR      ' copies PAR to ptr, so we can add 4 to point to the second long in i2c_data
    rdlong i2cdata1,ptr ' reads the first long into i2cdata1
    add    ptr,#4       ' points ptr to the second long, by adding 4 to it.
    rdlong i2cdata2,ptr ' reads the second long into i2cdata2
'
'
'

ptr      res 1
i2cdata1 res 1
i2cdata2 res 1

Hope this helps,
Baggers.

edit: put it in code box [noparse]:)[/noparse]

Neighborhood Physicist

Thanks, that helps alot.

Baggers

no problem [noparse]:)[/noparse]

Neighborhood Physicist

I am trying to used a shared resource to share data between cogs.

Below is the code. The I2CObject sends out the data in I2C_Data[noparse][[/noparse]0] and then sets it to zero when finished.
The spin code never sees the zero so the other numbers are never sent out.

Anyone have any idea why this doesn't work.

Thanks.


long I2C_Data
long waitamount
long I2CValue
long Shifter
long tmp
long zerotmp

OBJ
I2CObject : "I2CAssemblyObject"
PUB main

' Initialize the I2C_Data to 0
I2C_Data[noparse][[/noparse]0] := DataLong
I2C_Data := InfoLong
I2CObject.Start(@I2C_Data)
waitamount := 200_000
Shifter := MoveBit
zerotmp := 0
waitcnt(waitamount+cnt)
I2CValue:= DataLong
repeat
if I2C_Data[noparse][[/noparse]0] == 0 '<-- This statement is never true even though I am 99.999% sure that the assembly code sets it to zero
waitcnt(waitamount+cnt)
Shifter<-=1
tmp := AddressMask&Shifter
I2CValue := I2CValue&tmp
I2C_Data[noparse][[/noparse]0] := I2CValue

Mike Green

Please use the [noparse][[/noparse] code ] and [noparse][[/noparse] /code ] brackets around your code (without the spaces around "code" and "/code"). Without them, you lose the formatting. You also have to insert your own spaces around some subscripts since the forum display routines use some of them to set the font to be used and strips out what you think will display as subscripts.

Baggers

Neighborhood Physicist, ( had to correct myself from spelling it the english way then [noparse]:)[/noparse] )

few things, does that compile? if so, can you add the rest of the code? as I can't see DataLong or InfoLong's definition.

your also setting I2C_Data[noparse][[/noparse]0] to DataLong and in the next line I2C_Data to InfoLong, is I2C_Data one long or two, like your first post?

I've personally not used I2CAssemblyObject, but surely you have to send specific instructions over I2C? to request the data from a specific device? etc.

You either need to post more code, or at least state what DataLong and InfoLong is, and your intentions with it.

Baggers.