Leverage built in LED (#6)

* turn on LED on startup and blink for frequent activity

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f04c8b7..7629d9f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,12 +7,18 @@
 pico_sdk_init()
 
 add_executable(picoprobe
+        src/led.c
         src/main.c
         src/usb_descriptors.c
         src/probe.c
         src/cdc_uart.c
 )
 
+if (DEFINED ENV{PICOPROBE_LED})
+        message("PICOPROBE_LED is defined as " $ENV{PICOPROBE_LED})
+        target_compile_definitions(picoprobe PRIVATE PICOPROBE_LED=$ENV{PICOPROBE_LED})
+endif()
+
 set(DBG_PIN_COUNT=4)
 
 pico_generate_pio_header(picoprobe ${CMAKE_CURRENT_LIST_DIR}/src/probe.pio)

src/led.c

diff --git a/src/led.c b/src/led.c
new file mode 100644
index 0000000..65fc840
--- /dev/null
+++ b/src/led.c
@@ -0,0 +1,36 @@
+#include <pico/stdlib.h>
+#include <stdint.h>
+
+#include "picoprobe_config.h"
+
+#define LED_COUNT_SHIFT 14
+#define LED_COUNT_MAX 5 * (1 << LED_COUNT_SHIFT)
+
+static uint32_t led_count;
+
+void led_init(void) {
+    led_count = 0;
+
+    gpio_init(PICOPROBE_LED);
+    gpio_set_dir(PICOPROBE_LED, GPIO_OUT);
+    gpio_put(PICOPROBE_LED, 1);
+}
+
+
+
+void led_task(void) {
+    if (led_count != 0) {
+        --led_count;
+        gpio_put(PICOPROBE_LED, !((led_count >> LED_COUNT_SHIFT) & 1));
+    }
+}
+
+void led_signal_activity(uint total_bits) {
+    if (led_count == 0) {
+        gpio_put(PICOPROBE_LED, 0);
+    }
+
+    if (led_count < LED_COUNT_MAX) {
+        led_count += total_bits;
+    }
+}

src/led.h

diff --git a/src/led.h b/src/led.h
new file mode 100644
index 0000000..05bc250
--- /dev/null
+++ b/src/led.h
@@ -0,0 +1,8 @@
+#ifndef LED_H
+#define LED_H
+
+void led_init(void);
+void led_task(void);
+void led_signal_activity(uint total_bits);
+
+#endif

src/main.c

diff --git a/src/main.c b/src/main.c
index 9e54962..b67bef7 100644
--- a/src/main.c
+++ b/src/main.c
@@ -33,6 +33,7 @@
 #include "picoprobe_config.h"
 #include "probe.h"
 #include "cdc_uart.h"
+#include "led.h"
 
 // UART0 for Picoprobe debug
 // UART1 for picoprobe to target device
@@ -43,6 +44,7 @@
     cdc_uart_init();
     tusb_init();
     probe_init();
+    led_init();
 
     picoprobe_info("Welcome to Picoprobe!\n");
 
@@ -50,6 +52,7 @@
         tud_task(); // tinyusb device task
         cdc_task();
         probe_task();
+        led_task();
     }
 
     return 0;

src/picoprobe_config.h

diff --git a/src/picoprobe_config.h b/src/picoprobe_config.h
index f34c165..155745c 100755
--- a/src/picoprobe_config.h
+++ b/src/picoprobe_config.h
@@ -31,4 +31,17 @@
 #define PICOPROBE_UART_TX 4
 #define PICOPROBE_UART_RX 5
 
+// LED config
+#ifndef PICOPROBE_LED
+
+#ifndef PICO_DEFAULT_LED_PIN
+#error PICO_DEFAULT_LED_PIN is not defined, run PICOPROBE_LED=<led_pin> cmake
+#elif PICO_DEFAULT_LED_PIN == -1
+#error PICO_DEFAULT_LED_PIN is defined as -1, run PICOPROBE_LED=<led_pin> cmake
+#else
+#define PICOPROBE_LED PICO_DEFAULT_LED_PIN
+#endif
+
+#endif
+
 #endif
\ No newline at end of file

src/probe.c

diff --git a/src/probe.c b/src/probe.c
index f0cd2b3..2533f48 100755
--- a/src/probe.c
+++ b/src/probe.c
@@ -11,6 +11,7 @@
 #include <hardware/clocks.h>
 #include <hardware/gpio.h>
 
+#include "led.h"
 #include "picoprobe_config.h"
 #include "probe.pio.h"
 #include "tusb.h"
@@ -172,6 +173,9 @@
 
 void probe_handle_write(uint8_t *data, uint total_bits) {
     picoprobe_debug("Write %d bits\n", total_bits);
+
+    led_signal_activity(total_bits);
+
     probe_write_mode();
 
     uint chunk;