B4R Question Wemos SD card shield interface...

[rbghongade]

Dear friends,
I received my Micro SD Shield from Wemos http://www.wemos.cc/Products/micro_sd_shield.html
I was able to write code for analog data logging using Arduino IDE using Wemos Mini. How do we do the same in B4R? Is there such a library for interfacing shields (using SPI) to Wemos Mini (ESP8266)?
regards,

 

[Erel]

Have you tried to use rSD library: https://www.b4x.com/android/forum/threads/sd-cards.65994/ ?

 

[rbghongade]

Dear Erel,
I want a simple writing to SD card and am not able to follow the rSD example given in the link that you pointed at. The analog data is to be acquired , digitized and stored as it arrives. Attaching the Arduino sketch , where I was able to to do it. But I wish the same functionality in B4R.

 

[Erel]

The zip file is corrupted. rSD supports writing data. I'm not sure whether it is compatible with your shield or not. You need to test it.

 

[rbghongade]

Dear Erel,
The zip file has been replaced. I am in fact testing it right now , but it seems that the first value is overwritten every time. Not sure how to go to the next line. Tried adding CRLF also!

 

[Erel]

You need to post your code.

 

[rbghongade]

Here is my code:

Sub Process_Globals
   Public Serial1 As Serial
   Private timer1 As Timer
   Private sd As SD
   Private i As Int
 
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")
    sd.Initialize(4) '4 is the CS pin when using the ethernet shield
    timer1.Initialize("timer1_Tick", 1000)
    timer1.Enabled = True
End Sub

Sub Timer1_Tick
    Dim a As String
    Dim bc As ByteConverter
    Dim k(1) As Byte
sd.OpenReadWrite("DATALOG.TXT")
i=Rnd(0,1023)
a=i
k=bc.stringToBytes(a)
sd.Stream.WriteBytes(k,0,k.length)
sd.Close
Log(i)
End Sub

 

[Erel]

You have two options:
1. Leave the stream open instead of opening and closing it each time.

2. Set the stream position to the end of the file:

sd.Position = sd.CurrentFile.Size
sd.Stream.WriteBytes(...)

 

[rbghongade]

Hooray! Problem solved!
Erel is the GURU!

minor typo ,it should be
"sd.position=..." instead of "sd.stream.position"

 

[Erel]

Fixed.