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xyz-mIoT enabling the third UART how to

 

About xyz-mIoT shield


xyz-mIoT - Arduino programmable ARM0 shield

xyz-mIoT is an AT SAMD21G (ARM0) based shield family (16 models, including variants having BG96 / BG95-Mx / BC95G / EG91x / M95FA modem integrated) designed by itbrainpower.net.
Available models and info xyz-mIoT shield family and xyz-mIoT - Arduino ports mapping.

 

About xyz-mIoT and the third UART port


As default, the xyz-mIoT Arduino class gave you access to hardware UART ports Serial0 (dedicated for modem communication) and Serial1 port (available on RX0 and TX1 pads). Also two Serial ports are implemented via board USB-serial Arduino driver.

For certaign applications, the presence of the third UART port was requested. Bellow are some guidelines that enables this feature.


Credits: I would like to thank you to navr32 ==> github.com who gave us valuable info and insigts about this.


 

Enabling the third UART port on xyz-mIoT - how to


a. identify xyz-mIoT "variant.cpp" and add at the end of the "const PinDescription g_APinDescription" following lines:
// 44..45 Third xyz-mIot UART using Sercom2
{ PORTA, 14, PIO_SERCOM, (PIN_ATTR_DIGITAL), No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_14 }, // TX: SERCOM2/PAD[2]
{ PORTA, 15, PIO_SERCOM, (PIN_ATTR_DIGITAL), No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_15 }, // RX: SERCOM2/PAD[3]


Hints: - before doing this, you may like to make a backup of your variant.cpp
- "variant.cpp" should be found under Arduino hardware folder. Check in Arduino under File\Preferences\Settings menu tree.
Our is located "..Arduino15\packages\arduino\hardware\samd\1.6.17\variants\itbrainpower.net_xyz-mIOT".


b. Make a folder named "Serial2_echo_02".
Copy the code bellow, paste it one new file and save the file as "Serial2_echo_02.ino" in the folder created in previously or, you may download it from here (right click & save as): enabling the third UART porton xyz-mIoT, Arduino code

1/* Serial2 echo - enabling the third UART port on xyz-mIoT shields - v0.2/20230301.  
2*
3* Serial2 RX and TX definitions should be added in variant.cpp 
4* usual path ==> "C:\Users\.........\Arduino15\packages\arduino\hardware\samd\1.6.17\variants\itbrainpower.net_xyz-mIOT\variant.cpp"
5
6* add at the end of the "const PinDescription g_APinDescription" following 3 lines:
7* // 44..45 Third xyz-mIot UART using Sercom2
8* { PORTA, 14, PIO_SERCOM, (PIN_ATTR_DIGITAL), No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_14 }, // TX: SERCOM2/PAD[2]
9* { PORTA, 15, PIO_SERCOM, (PIN_ATTR_DIGITAL), No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_15 }, // RX: SERCOM2/PAD[3]
10*
11* COMPATIBILITY: this is compatible with all xyz-mIoT shields https://itbrainpower.net/xyz-mIoT/
12*
13* We ask you to use this SOFTWARE only in conjunction with xyz-mIoT shields(s) breakout usage. Modifications, derivates 
14* and redistribution of this SOFTWARE must include unmodified this notice. You can redistribute this SOFTWARE and/or modify it under the 
15* terms of this notice. 
16
17* This SOFTWARE is distributed is provide "AS IS" in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 
18* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19*  
20* itbrainpower.net invests significant time and resources providing those how to and in design phase of our IoT products.
21* Support us by purchasing our xyz-mIoT shields from https://itbrainpower.net/order#xyz-mIoT
22*
23* I would like to thank you to navr32 ==> github.com who gave us valuable info and insigts about this.
24*
25* Dragos Iosub, Bucharest 2023.
26* https://itbrainpower.net
27*/
28
29#define PIN_SERIAL2_RX       (45ul)               //RX digital pin 5 [mapped also as 45]
30#define PIN_SERIAL2_TX       (44ul)               //TX digital pin 2 [mapped also as 44]
31#define PAD_SERIAL2_TX       (UART_TX_PAD_2)
32#define PAD_SERIAL2_RX       (SERCOM_RX_PAD_3)
33
34// Let's init the Serial2 class
35Uart Serial2(&sercom2, PIN_SERIAL2_RX, PIN_SERIAL2_TX, PAD_SERIAL2_RX, PAD_SERIAL2_TX);
36
37void setup() 
38{
39  Serial2.begin(115200);            // INIT Serial2
40  SerialUSB.begin(115200);          // INIT SerialUSB - just to have it as debug
41  delay (2000);
42  Serial2.println("test third UART on xyz-mIoT");
43  SerialUSB.println("test third UART on xyz-mIoT");
44  
45}
46
47void loop() 
48{  
49  if (Serial2.available())            // Data available?
50  {
51    byte byteRead = Serial2.read();   // Read byte  
52    Serial2.write(byteRead);          // Echo the read byte
53    SerialUSB.write(byteRead);        // Write the read byte on SerialUSB
54  }
55}
56
57void SERCOM2_Handler()                // IRQ handler for SERCOM2
58{
59  Serial2.IrqHandler();
60}
61


HINT:
        TX <--> xyz-mIoT D2
        RX <--> xyz-mIoT D5


TUTORIAL PROVIDED WITHOUT ANY WARRANTY!!! USE IT AT YOUR OWN RISK!!!!

 

 

 

 

 

 

Original how to written by Dragos Iosub & itbrainpower.net team

 

 

 

 

document version 1.02 / 2023-03-01 © R&D Software Solutions srl