Userspace LED Matrix Driver

include/drivers/driver_enums.hpp

@@ -9,6 +9,8 @@ enum class DriverCommand {
     BUTTONS = 2,
     TERMINAL_OUTPUT = 3,
     TIMER_CANCEL = 4,
+    SET_PIN = 5,
+    CLEAR_PIN = 6,
 };
 
 enum class DriverSubscribe { NOTIFY_BUTTON_PRESS = 0, TIMER_START = 1 };

include/userlib/syscalls.hpp

@@ -32,6 +32,10 @@ start_timer(void (*callback)(uint32_t), uint32_t microseconds, bool periodic = f
 
 void cancel_timer(uint32_t timer_id);
 
+void set_pin(uint32_t pin);
+
+void clear_pin(uint32_t pin);
+
 // We need a syscall for this because SVC will not be preempted by SysTick
 // Technically this is insecure - it's mostly for debugging
 void debug_print(const char* string);

src/drivers/driver_commands.cpp

@@ -4,6 +4,7 @@
 #include "drivers/driver_enums.hpp"
 #include "drivers/led_display.hpp"
 #include "drivers/virtual_timer_controller.hpp"
+#include "hal/gpio_wrapper.hpp"
 
 #include <stdio.h>
 
@@ -35,6 +36,12 @@ etl::optional<int> handle_command(DriverCommand type, int arg1, int arg2, int ar
                 static_cast<uint32_t>(arg1)
             );
             break;
+        case DriverCommand::SET_PIN:
+            edge::aidan::set_gpio_pin(static_cast<uint32_t>(arg1));
+            break;
+        case DriverCommand::CLEAR_PIN:
+            edge::aidan::clear_gpio_pin(static_cast<uint32_t>(arg1));
+            break;
     }
     return etl::nullopt;
 }

src/entrypoint.cpp

@@ -9,17 +9,20 @@
 extern void ipc_part1(void);
 extern void ipc_part2(void);
 extern void exception_task(void);
+extern void led_matrix_task(void);
 
 int main(void)
 {
     printf("Starting EdgeOS\n");
 
     edge::FaultHandler::get();
 
-    edge::scheduler.add_task(exception_task);
+    /* edge::scheduler.add_task(exception_task); */
 
-    edge::scheduler.add_task(ipc_part1);
-    edge::scheduler.add_task(ipc_part2);
+    /* edge::scheduler.add_task(ipc_part1); */
+    /* edge::scheduler.add_task(ipc_part2); */
+
+    edge::scheduler.add_task(led_matrix_task);
 
     edge::scheduler.start_scheduler();
 }

src/user_programs/user_program_led_matrix.cpp

@@ -0,0 +1,66 @@
+#include "hal/gpio_wrapper.hpp"
+#include "microbit_v2.h"
+#include "scheduler/pending_process_callbacks.hpp"
+#include "userlib/syscalls.hpp"
+
+#include <stdint.h>
+
+#include <cstdio>
+
+uint8_t row_index = 0;
+bool led_states[5][5] = {false};
+uint32_t rows[] = {LED_ROW1, LED_ROW2, LED_ROW3, LED_ROW4, LED_ROW5};
+uint32_t cols[] = {LED_COL1, LED_COL2, LED_COL3, LED_COL4, LED_COL5};
+
+static uint8_t control_row = 0;
+static uint8_t control_col = 0;
+
+void upkeep_led_matrix(uint32_t id)
+{
+    edge::userlib::clear_pin(rows[0]);
+    edge::userlib::clear_pin(rows[1]);
+    edge::userlib::clear_pin(rows[2]);
+    edge::userlib::clear_pin(rows[3]);
+    edge::userlib::clear_pin(rows[4]);
+    for (int col_index = 0; col_index < 5; ++col_index) {
+        bool state = led_states[row_index][col_index];
+        if (!state) {
+            edge::userlib::set_pin(cols[col_index]);
+        }
+        else {
+            edge::userlib::clear_pin(cols[col_index]);
+        }
+    }
+    edge::userlib::set_pin(rows[row_index]);
+    row_index++;
+    row_index = row_index % 5;
+}
+
+void update_led_states(uint32_t id)
+{
+    bool st = led_states[control_row][control_col];
+    led_states[control_row][control_col] = !st;
+
+    control_col++;
+    if (control_col == 5) {
+        control_row++;
+        control_col = 0;
+    }
+    control_row %= 5;
+}
+
+void led_matrix_task(void)
+{
+    using namespace edge::userlib;
+    // We want to call this so that the led_matrix driver sets up all the directions of
+    // the pins so we don't have to...
+    set_led(2, 2, true);
+    set_led(2, 2, false);
+
+    start_timer(upkeep_led_matrix, 2'000, true);
+    start_timer(update_led_states, 10'000, true);
+
+    while (1) {
+        yield();
+    }
+}

src/userlib/syscalls.cpp

@@ -103,6 +103,20 @@ void USER_CODE cancel_timer(uint32_t timer_id)
     TRIGGER_SVC(SystemCallType::COMMAND);
 }
 
+void USER_CODE set_pin(uint32_t pin)
+{
+    SET_REGISTER(r0, (int)drivers::DriverCommand::SET_PIN);
+    SET_REGISTER(r1, (int)pin);
+    TRIGGER_SVC(SystemCallType::COMMAND);
+}
+
+void USER_CODE clear_pin(uint32_t pin)
+{
+    SET_REGISTER(r0, (int)drivers::DriverCommand::CLEAR_PIN);
+    SET_REGISTER(r1, (int)pin);
+    TRIGGER_SVC(SystemCallType::COMMAND);
+}
+
 void USER_CODE debug_print(const char* val)
 {
     SET_REGISTER(r0, (int)drivers::DriverCommand::TERMINAL_OUTPUT);