fixup in uart.md (clean code, erase comments, grammar)

uart.md

@@ -6,6 +6,8 @@ date: 2025/01/30
 licence: MIT
 ---
 
+[Back](CooperativeMultitasking.html)
+
 > This is not a state machine, per se. This page is included because
 > I found it very common to need UART communication, and I found I could
 > fit it into the *event-dispatcher* system pretty easily.
@@ -64,12 +66,12 @@ be sent or processed:
 
 /* circular buffers */
 
-char tx_buffer[TX_SIZE];        // the largest packet we need to tx is 50 bytes
+char tx_buffer[TX_SIZE];        
 char *tx_next_empty = tx_buffer, *tx_next_send = tx_buffer;
 const char * const tx_end = tx_buffer + TX_SIZE;
 
 
-char rx_buffer[RX_SIZE];        // the largest packet we need to rx is 192 bytes
+char rx_buffer[RX_SIZE];       
 char *rx_next_empty = rx_buffer, *rx_next_rcv = rx_buffer;
 const char * const rx_end = rx_buffer + RX_SIZE;
 ```
@@ -105,7 +107,8 @@ is ready.
 
 The `uartGetChar()` checks the rx buffer, and returns a char if one is available 
 (-1 otherwise). The `uartCheckChar()` and `uartGetCharCount()`
-let the designer check the first character of a command string, and determine 
+let the designer check the first character of a command string, decide if
+it is relevant to a specific task, plus determine 
 whether the command has been fully loaded into the rxBuffer.
 
 Here is a fully functional module that implements the above:
@@ -117,12 +120,12 @@ Here is a fully functional module that implements the above:
 
 /* circular buffers */
 
-char tx_buffer[TX_SIZE];        // the largest packet we need to tx is 50 bytes
+char tx_buffer[TX_SIZE];      
 char *tx_next_empty = tx_buffer, *tx_next_send = tx_buffer;
 const char * const tx_end = tx_buffer + TX_SIZE;
 
 
-char rx_buffer[RX_SIZE];        // the largest packet we need to rx is 192 bytes
+char rx_buffer[RX_SIZE];     
 char *rx_next_empty = rx_buffer, *rx_next_rcv = rx_buffer;
 const char * const rx_end = rx_buffer + RX_SIZE;
 ```
@@ -173,6 +176,29 @@ void uartDiscardChar(int i) {
         uartGetChar();
 }
 
+/** add character to the tx buffer
+ * @return -1 if the buffer is full
+ * */
+char uartSendChar(char c) {
+    *tx_next_empty = c;             // increment AFTER adding to queue
+    if (++tx_next_empty >= tx_end)
+        tx_next_empty = tx_buffer;
+    if (tx_next_empty == tx_next_send) 
+        c = -1;
+    // if the USART is empty, trigger the first send
+    if (USART2->ISR & 0x80) 
+        USART2->CR1 |= 0x80;            // enable the tx interrupt
+    return c;
+}
+
+/** send a string a specified length out the uart */
+void uartSendString(const char* p, int len) {
+        while (len--)
+                uartSendChar(*p++);
+}       
+
+/* ============ INTERRUPTS =================== */
+
 /* the for a RX character
  * deposit it into the buffer, issue a EVT_CHAR and return
  */ 
@@ -184,6 +210,7 @@ void uart_rx_isr(void) {
   newEvent(EVT_CHAR);     // inform all tasks that there is 
                           // something in the rx buffer
 }
+
 void uart_tx_isr(void) {
     // the uart tx is empty
     // if there is tx data available to send, push it into the uart
@@ -197,26 +224,5 @@ void uart_tx_isr(void) {
       USART2->CR1 &= ~0x80;  
 }
 
-
-/** add character to the tx buffer
- * @return -1 if the buffer is full
- * */
-char uartSendChar(char c) {
-    *tx_next_empty = c;             // increment AFTER adding to queue
-    if (++tx_next_empty >= tx_end)
-        tx_next_empty = tx_buffer;
-    if (tx_next_empty == tx_next_send) 
-        c = -1;
-    // if the USART is empty, trigger the first send
-    if (USART2->ISR & 0x80) 
-        USART2->CR1 |= 0x80;            // enable the tx interrupt
-    return c;
-}
-
-/** send a string a specified length out the uart */
-void uartSendString(const char* p, int len) {
-        while (len--)
-                uartSendChar(*p++);
-}       
 ```