B4R Question Translate Code (Logical AND......)

mw71

Active Member
Licensed User
hi,

i would like "Translate" this Code to B4R:
https://www.qrp-labs.com/images/synth/demo4/oscillator.ino

i have problem with some Lines:
B4X:
Si5351a_Write_Reg (26, (MSNA_P3 & 65280) >> 8);
'-> Logical AND and SHIFT (?)
and with this:
B4X:
while (outdivider > 900){            // If output divider out of range (>900) use additional Output divider
   R = R * 2;
   outdivider = outdivider / 2;
}
if (outdivider % 2) outdivider--;    // finds the even divider which delivers the intended Frequency

How can i write this in B4R (or it is better to use the C Code?)
 

sorex

Expert
Licensed User
the first one would be

B4X:
Bit.ShiftRight(Bit.And(MSNA_P3,65280),8)

or

Bit.And(MSNA_P3,65280) / 256  'destination must be INT

second one would be

B4X:
if outdivider mod 2=0 then outdivider=outdivider-1
 
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mw71

Active Member
Licensed User
Thank You!!

i have see a other "Problem":
B4X:
Si5351a_Write_Reg (31, ((MSNA_P3 & 983040) >> 12) | ((MSNA_P2 & 983040) >> 16));

'-> Solution (hope it's correct :)

Si5351a_Write_Reg (31, Bit.Or(Bit.ShiftRight(Bit.And(MSNA_P3,983040),12),Bit.ShiftRight(Bit.And(MSNA_P2,983040),16))) ' Parts of MSNA_P3 und MSNA_P1
@sorex, you write: destination must be INT
the Sub Si5351a_Write_Reg:
B4X:
Sub Si5351a_Write_Reg (regist As Byte, value As ULong)                'Writes "byte" into "regist" of Si5351a via I2C
    i2C.WriteTo(SI5351_Adress, Array As Byte(regist))                      ' Writes a byte containing the number of the register
    i2C.WriteTo(SI5351_Adress, Array As Byte(value))                        ' Writes a byte containing the value To be written in the register
    ' Sends the data And ends the transmission
End Sub
is this correct? i am not sure with the translate/split from ULong/UInt to Byte
 

sorex

Expert
Licensed User
1 seems right.

2 I don't know about the function. is there uLong in B4X?

I guess you'll need to split it up like

B4X:
i2C.WriteTo(SI5351_Adress, bit.and(value,255))  'low byte
i2C.WriteTo(SI5351_Adress, bit.shiftRight(value,8)) 'high byte
if the register only supports 0-255 then you only need the first line.
 

emexes

Well-Known Member
Licensed User
I agree that your translation of the first case looks correct, assuming that the MSNA values are 32-bit. The mask value 983040 would be much clearer as 0xF0000, so that you can see it gives you the first four bits of the high 16-bit word.

The second case looks plausibly correct too, although:
2a/ I would change the datatype of the value parameter to match the register (seems to be a Byte, not a Ulong) and,
2b/ given the .WriteTo routine looks capable of handling multiple bytes, I would expect to write both regist and value in the same operation, eg:
B4X:
Sub Si5351a_Write_Reg (regist As Byte, value As Byte)           'writes "value" into "regist" of Si5351a via I2C
    i2C.WriteTo(SI5351_Adress, Array As Byte(regist, value))    'first the register address, then the value
End Sub
but if your code works, then obviously my expectation is wrong ;-)

What does the already-working C code look like?
 
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