From e68e31de1c419fe4e500cdf1d0f8ca6de2964dcc Mon Sep 17 00:00:00 2001
From: Nao Pross <naopross@thearcway.org>
Date: Fri, 4 May 2018 19:13:38 +0200
Subject: Implement uart TX features

---
 hal/uart.hpp |  4 ++--
 hal/uart.tpp | 57 ++++++++++++++++++++++++++++++++++++++++++++-------------
 main.cpp     | 20 +++++++++++---------
 3 files changed, 57 insertions(+), 24 deletions(-)

diff --git a/hal/uart.hpp b/hal/uart.hpp
index 096ac7b..0be5835 100644
--- a/hal/uart.hpp
+++ b/hal/uart.hpp
@@ -43,8 +43,8 @@ namespace uart
         tx_empty = 1<<4,
     };
 
-    std::queue<uint8_t> rx_buffer[devices_count];
-    std::queue<uint8_t> tx_buffer[devices_count];
+    std::queue<uint8_t> _rx_buffer[devices_count];
+    std::queue<uint8_t> _tx_buffer[devices_count];
 
     template<unsigned dev>
     void initialize();
diff --git a/hal/uart.tpp b/hal/uart.tpp
index 8c120ec..e4b722e 100644
--- a/hal/uart.tpp
+++ b/hal/uart.tpp
@@ -26,22 +26,22 @@ extern "C" {
 namespace uart
 {
     template<unsigned dev>
-    bool rx_buffer_empty()
+    inline std::queue<uint8_t>& rx_buffer()
     {
-        return rx_buffer[dev -1].empty();
+        return uart::_rx_buffer[dev -1];
     }
 
     template<unsigned dev>
-    bool tx_buffer_full()
+    inline std::queue<uint8_t>& tx_buffer()
     {
-        return !tx_buffer[dev -1].empty();
+        return uart::_tx_buffer[dev -1];
     }
 
     template<unsigned dev>
     uint8_t read()
     {
-        uint8_t byte = rx_buffer[dev -1].front();
-        rx_buffer[dev -1].pop();
+        uint8_t byte = rx_buffer<dev>().front();
+        rx_buffer<dev>().pop();
 
         return byte;
     }
@@ -51,7 +51,7 @@ namespace uart
     {
         uint8_t *bptr = buffer;
         unsigned len = numbytes;
-        
+
         while (len--) {
             *(bptr++) = read<dev>();
         }
@@ -60,12 +60,20 @@ namespace uart
     template<unsigned dev>
     void write(const uint8_t byte)
     {
+        // disable send data flag
+        IEC1bits.U1TXIE = 0;
+
+        tx_buffer<dev>().push(byte);
 
+        // enable send data flag
+        IEC1bits.U1TXIE = 1;
     }
 
     template<unsigned dev>
     void write(const std::string &str)
     {
+        // TODO: if size of str is reasonale, push to queue AND THEN send
+        //       right now on each call the interrupt is enabled and disabled
         for (const char &c : str) {
             write<dev>(c);
         }
@@ -74,7 +82,12 @@ namespace uart
     template<unsigned dev>
     unsigned write(const uint8_t *buffer, const unsigned numbytes)
     {
+        uint8_t *bptr = buffer;
+        unsigned len = numbytes;
 
+        while (len--) {
+            write<dev>(*(bptr++));
+        }
     }
 }
 
@@ -83,26 +96,44 @@ namespace uart
 
 // debug
 #include "pin.tpp"
-pin<2> led_blue(&LATBbits, &TRISBbits, &PORTEbits);
+pin<2> led_blue(&LATBbits, &TRISBbits, &PORTBbits);
+pin<3> led_green(&LATBbits, &TRISBbits, &PORTBbits);
 
 void __ISR(_UART_1_VECTOR, IPL1AUTO) usart_1_isr()
 {
     if (IFS1bits.U1RXIF) {
         // debug
         led_blue.toggle();
-        while (U1STAbits.URXDA) {
-            uart::rx_buffer[0].push(static_cast<uint8_t>(U1RXREG));
-        }
+
+        // wait for data to be available
+        while (!U1STAbits.URXDA);
+        uart::rx_buffer<1>().push(static_cast<uint8_t>(U1RXREG));
 
         IFS1bits.U1RXIF = 0;
-    } else if (IFS1bits.U1TXIF) {
+
+    } 
+    // on each interrupt call, send one character
+    else if (IFS1bits.U1TXIF) {
+        // if empty, disable send data flag
+        if (uart::tx_buffer<1>().empty()) {
+            IEC1bits.U1TXIE = 0;
+            return;
+        }
+
+        led_green.toggle();
+
+        // write data
+        U1TXREG = static_cast<decltype(U1TXREG)>(uart::tx_buffer<1>().front());
+        uart::tx_buffer<1>().pop();
+
         IFS1bits.U1TXIF = 0;
+
     } else {
         if (U1STAbits.OERR == 1) {
             U1STAbits.OERR = 0;
         }
 
-        IFS1bits.U1TXIF = 0;
+        IFS1bits.U1EIF = 0;
     }
 }
 
diff --git a/main.cpp b/main.cpp
index 119e5ce..d95bc74 100644
--- a/main.cpp
+++ b/main.cpp
@@ -5,8 +5,7 @@
  * Created on May 1, 2018, 6:18 PM
  */
 
-#include <stdio.h>
-#include <stdlib.h>
+#include <string>
 
 // basic devices
 #include "hal/confbits.hpp"
@@ -18,7 +17,7 @@
 
 extern "C" {
     #include <xc.h>
-    #include <proc/p32mx470f512h.h>
+    // #include <proc/p32mx470f512h.h>
 }
 
 
@@ -36,15 +35,18 @@ int main(int argc, char** argv)
     led1.set(1);
     led2.set(1);
     led3.set(1);
+
+    uart::write<1>("started\n\r");
     
     while (true) {
-        while (uart::rx_buffer_empty<1>());
-//        while (!uart::rx_buffer_empty<1>()) {
-//            uart::write<1>(uart::read<1>());
-//            uart::write<1>("\n\rk")
-//        }
+        while (uart::rx_buffer<1>().empty());
+
+        while (!uart::rx_buffer<1>().empty()) {
+            uint8_t c = uart::read<1>();
+            uart::write<1>(c);
+            uart::write<1>("\n\r");
+        }
         
-        uart::read<1>();        
         led1.toggle();
     }
 
-- 
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