IRQ driven RX on UART0

See examples/terminal/ for usage

examples/terminal/FreeRTOSConfig.h

@@ -0,0 +1,12 @@
+/* Terminal FreeRTOSConfig overrides.
+
+   This is intended as an example of overriding some of the default FreeRTOSConfig settings,
+   which are otherwise found in FreeRTOS/Source/include/FreeRTOSConfig.h
+*/
+
+/* The serial driver depends on counting semaphores */
+#define configUSE_COUNTING_SEMAPHORES 1
+
+/* Use the defaults for everything else */
+#include_next<FreeRTOSConfig.h>
+

examples/terminal/Makefile

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+PROGRAM=terminal
+EXTRA_COMPONENTS=extras/serial-driver
+include ../../common.mk

examples/terminal/terminal.c

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+/* Serial terminal example
+ * UART RX is interrupt driven
+ * Read characters until \n and echo back
+ *
+ * This sample code is in the public domain.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <espressif/esp_common.h>
+#include <serial_driver.h>
+
+#define BUFFER_SIZE (81)
+
+void user_init(void)
+{
+    char buffer[BUFFER_SIZE];
+    uint32_t i = 0;
+    sdk_uart_div_modify(0, UART_CLK_FREQ / 115200);
+    while(1) {
+        char ch;
+        // The thread will block here until there is data available
+        // NB. read(...) may be called from user_init or from a thread
+        // We can check how many characters are available in the RX buffer
+        // with uint32_t uart0_num_char(void);
+        if (read(0, (void*)&ch, 1)) { // 0 is stdin
+            if (i == BUFFER_SIZE-2 || ch == '\n') {
+                buffer[i] = 0;
+                printf("Unknown command: %s\n", (char*) buffer);
+                i = 0;
+            } else {
+                buffer[i++] = ch;
+            }
+        }
+    }
+}