add better code for arduino uart helper

Author: verilog-indeed

gowin_empu/README.md

@@ -449,22 +449,38 @@ Each C file gets a listing inside the Debug directory, for example the "main.c"
 		}
 	</details>
 
-* Connect pin 19 of the Nano 4K to a USB-UART converter, and add a pull-up resistor (10k ish or so should be good) to the Vcc of the converter. We set the UART TX pin to open-drain configuration which means the pull-up is necessary to actually see any kind of signal, I'm using an Arduino Uno which has the ability to add internal 5V pull-up resistors. The Arduino sketch I used is provided here for reference (it's probably not the best implementation but it works).
+* Connect pin 19 of the Nano 4K to a USB-UART converter, and add a pull-up resistor (10k ish or so should be good) to the Vcc of the converter. We set the UART TX pin to open-drain configuration which means the pull-up is necessary to actually see any kind of signal, I'm using an Arduino Uno which has the ability to add internal 5V pull-up resistors.
+* * The Arduino sketch I used is provided here for reference (it's probably not the best implementation but it works, connect pin 19 of the Nano 4K to pin 7 of the Uno).
+
 	<details>
 			<summary><b>Show code</b></summary>
 
+		#include <SoftwareSerial.h>
+		
+		#define rxPin 7;
+		#define txPin 6;
+		
+		SoftwareSerial softUart (rxPin, txPin);
 		
 		void setup() {
-			Serial.begin(9600);
-			pinMode(0, INPUT_PULLUP);
+		  Serial.begin(9600);
+		  softUart.begin(9600);
+  		  pinMode(rxPin, INPUT_PULLUP);
 		}
-
-		void loop() {} 
-
-		void serialEvent() {
-			while (Serial.available()) {
-				Serial.print((char)Serial.read());
-			}
+		
+		void loop() {
+		  if (softUart.available()) {
+		    char c =  mySerial.read();
+		    Serial.print(c);
+		  }
+		  if (Serial.available()) {
+		    char c = Serial.read();
+		    softUart.print(c);
+  
+		    //Gowin EMPU's UART isn't buffered, sending characters 
+  		    //too fast results in some of them being missed
+		    delay(1); 
+		  }
 		}
 
 	</details>
@@ -589,4 +605,4 @@ Relevant Gowin documentation:
 * [Gowin_EMPU IDE user guide (IPUG928E)](http://cdn.gowinsemi.com.cn/IPUG928E.pdf) for more information on the usage of J-Link debuggers, Keil MDK and more.
 * [Gowin_EMPU Software Design(IPUG931E)](http://cdn.gowinsemi.com.cn/IPUG931E.pdf) for the EMPU's memory map, peripheral register definition and more.
 * [Gowin_EMPU Hardware Design(IPUG932E)](http://cdn.gowinsemi.com.cn/IPUG932E.pdf) for signal definition, peripheral details and more.
-* [The latest version of GW1NS-4C example projects and libraries from Gowin](https://cdn.gowinsemi.com.cn/Gowin_EMPU(GW1NS-4C)_V1.1.3.zip). Make sure to alter SRAM and clock configurations to match your FPGA design setup.
+* [The latest version of GW1NS-4C example projects and libraries from Gowin](https://cdn.gowinsemi.com.cn/Gowin_EMPU(GW1NS-4C)_V1.1.3.zip). Make sure to alter SRAM and clock configurations to match your FPGA design setup.