converting char to unsigned char

Projects Programming
1

Hi,

I'm wondering, is it possible to convert char to unsigned char?
I get a compiling error with this code:

  if ( !strcmp(packetBuffer, "%03d")) {
    tableID = packetBuffer;
    EEPROM.put(address, tableID);
    if (EEPROM.commit()) {
      Serial.println("EEPROM successfully committed -- TABLE ID is updated");
      Udp.beginPacket(Udp.remoteIP(), destinationPort);
      String text = "New table ID is: ";
      String toSend = text + tableID;
      Udp.print(toSend);
      Udp.endPacket();
      //resetFunc(); ///RESET CODE(!)
    } else {
      Serial.println("ERROR! EEPROM commit failed");
    }
  }

in this case 'tableID' is unsigned char and 'packetBuffer' is char.
I'm trying to capture 3 digits from a UDP packet and put them in tableID.

Since I have a lot of code, I don't want to change the types directly, so is there a way to convert it easy?

2

'packetBuffer' is char.

I hope packetBuffer is a char*.

Post code.
Post error messages.

3

TheMemberFormerlyKnownAsAWOL:
I hope packetBuffer is a char*.

Post code.
Post error messages.

char packetBuffer[256]; //buffer to hold incoming packet

unsigned char tableID;

It is quite a project, so please find code attached.
This is the compile error:

invalid conversion from 'char*' to 'unsigned char' [-fpermissive]

Terraslampv10.ino (23.4 KB)

4

Post the COMPLETE error message.

5

gfvalvo:
Post the COMPLETE error message.

Find attached ( to long to share directly )

errorMsg.txt (73.7 KB)

6

Since 'packetBuffer' is an array of char, it's name is essentially a pointer to a char (aka char *). This:

tableID = (unsigned char)packetBuffer;

is an error since you can't cast a pointer to an (unsigned char).

7

gfvalvo:
Since 'packetBuffer' is an array of char, it's name is essentially a pointer to a char (aka char *). This:

tableID = (unsigned char)packetBuffer;

is an error since you can't cast a pointer to an (unsigned char).

I've also tried simply tableID = packetBuffer; like I've shown in my first post, which also did not succeed.
Is there someway possible to assign the incoming packet to 'tableID' ?

8

packetBuffer is an array that can contain as many as 256 characters (255 if it's a null-terminated c-string):

char packetBuffer[256];

tableID is an unsigned char:

unsigned char tableID;

That means it can only hold one byte (eight bits) of data. So, it can't possibly hold the contents of packetBuffer.