Nuts and Volts - December 2015

■ Screenshot 7. A good programmer uses every trick at his or her disposal. This capture shows how I determined the Peripheral MAC address.

■ Screenshot 6. This is a familiar shot. Note the reduced number of GPIO pins required to support the RN4020 click. These are the only pins that the click brings out to its headers.

MLDP mode, which allows us to communicate with ASCII characters. Let’s send a tilde character (~) once per second:

if(rxBuf[0] == ‘C’ && \
 rxBuf[1] == ‘M’ && \
 rxBuf[2] == ‘D’)
{
 printf(“E,0,001EC01D7D9B\r\n”);
 //connect to Peripheral
 __delay_ms(100);
 CMD_SetHigh(); //enter MLDP mode
}
 do{
 __delay_ms(1000);
 printf(“~”);
 
 }while(1);

We didn’t code the Peripheral to process the tilde. So, we can go back to the peripheral project and add the code. We can also use one of the Curiosity board’s LEDs to indicate that the tilde character is getting processed. A quick look at the Curiosity schematic (in the Curiosity User’s Guide) tells us that we can access LED D7 via RC5 of the PIC16F1619. I added the RC5 pin using the Code

■ Screenshot 8. I simply added the RC5 pin as OURLED and regenerated the GPIO code. Macros for the new GPIO pin were seamlessly added to the original code.

 __delay_ms(500);
 if(EUSART_DataReady)
 {
 do{
 rxBuf[indx++] = EUSART_Read();
 }while(EUSART_DataReady);
 }
}

Once the Central comes up, it will need to connect to our original peripheral. We’re going to cheat a little and use an RN4020 PICtail to obtain the peripheral’s public

 indx = 0;
 do{
 if(EUSART_DataReady)
 {
 do{
 rxBuf[indx] = EUSART_Read();
 if(rxBuf[indx] == ‘~’)
 {
 OURLED_Toggle();
//blink  LED D7 on Curiosity Development Board
 }
 }while(EUSART_DataReady);
 }
  }while(1);

MAC address. The process is captured in Screenshot 7.

We could have written scan code to get this address, but since we’re only concerned with a peer-to-peer connection, I decided to go the cheap and easy way.

By the way, when the Peripheral establishes a connection, LED D4 will illuminate on the Peripheral Curiosity development board. The Master indicates a connection by the CONN LED on the click module.

Here’s the Master connection code that was added to the original peripheral code:

Still Curious?

You’ve got to try this on your own. I’ll supply the project files we used via the article link. In the meantime, you can now add Curiosity to your design cycle. NV