exercises: add Exercise 08 SystemStartup scaffold with early SPI deselect and SD/OLED startup orchestration

2026-02-16 18:18:32 -08:00 · 2026-02-16 18:18:32 -08:00 · 322a77bfe4
commit 322a77bfe4
parent 2aec641fc2
9 changed files with 720 additions and 0 deletions
--- a/exercises/08_SystemStartup/lib/system_startup/SystemStartup.cpp
+++ b/exercises/08_SystemStartup/lib/system_startup/SystemStartup.cpp
@ -0,0 +1,96 @@
+#include "SystemStartup.h"
+
+#include <Wire.h>
+#include <U8g2lib.h>
+
+#ifndef OLED_SDA
+#define OLED_SDA 17
+#endif
+
+#ifndef OLED_SCL
+#define OLED_SCL 18
+#endif
+
+#ifndef OLED_ADDR
+#define OLED_ADDR 0x3C
+#endif
+
+static const bool kEnableOled = true;
+
+static U8G2_SH1106_128X64_NONAME_F_HW_I2C g_oled(U8G2_R0, /* reset=*/U8X8_PIN_NONE);
+static SystemStartup* g_activeSystemStartup = nullptr;
+
+static void forceSpiDeselectedEarly() {
+  pinMode(tbeam_supreme::sdCs(), OUTPUT);
+  digitalWrite(tbeam_supreme::sdCs(), HIGH);
+  pinMode(tbeam_supreme::imuCs(), OUTPUT);
+  digitalWrite(tbeam_supreme::imuCs(), HIGH);
+}
+
+SystemStartup::SystemStartup(Print& serial) : serial_(serial), sd_(serial) {}
+
+bool SystemStartup::begin(const SystemStartupConfig& cfg, SystemEventCallback callback) {
+  cfg_ = cfg;
+  callback_ = callback;
+  g_activeSystemStartup = this;
+
+  // Match Exercise 05 behavior: deselect SPI devices immediately at startup.
+  forceSpiDeselectedEarly();
+
+  if (kEnableOled) {
+    Wire.begin(OLED_SDA, OLED_SCL);
+    g_oled.setI2CAddress(OLED_ADDR << 1);
+    g_oled.begin();
+  }
+
+  emit(SystemEvent::BOOTING, "System startup booting");
+  oledShow3("System Startup", "Booting...");
+
+  serial_.printf("Sleeping for %lu ms to allow Serial Monitor connection...\r\n",
+                 (unsigned long)cfg_.serialDelayMs);
+  delay(cfg_.serialDelayMs);
+
+  return sd_.begin(cfg_.sd, &SystemStartup::onSdEventThunk);
+}
+
+void SystemStartup::update() {
+  sd_.update();
+}
+
+void SystemStartup::onSdEventThunk(SdEvent event, const char* message) {
+  if (g_activeSystemStartup != nullptr) {
+    g_activeSystemStartup->onSdEvent(event, message);
+  }
+}
+
+void SystemStartup::onSdEvent(SdEvent event, const char* message) {
+  if (event == SdEvent::NO_CARD) {
+    oledShow3("SD missing or", "invalid FAT16/32", "Insert/format card");
+    emit(SystemEvent::SD_MISSING, message);
+  } else if (event == SdEvent::CARD_MOUNTED) {
+    oledShow3("SD card ready", "Mounted OK");
+    emit(SystemEvent::SD_READY, message);
+  } else if (event == SdEvent::CARD_REMOVED) {
+    oledShow3("SD card removed", "Please re-insert");
+    emit(SystemEvent::SD_REMOVED, message);
+  }
+}
+
+void SystemStartup::emit(SystemEvent event, const char* message) {
+  serial_.printf("[SYSTEM] %s\r\n", message);
+  if (callback_ != nullptr) {
+    callback_(event, message);
+  }
+}
+
+void SystemStartup::oledShow3(const char* l1, const char* l2, const char* l3) {
+  if (!kEnableOled) {
+    return;
+  }
+  g_oled.clearBuffer();
+  g_oled.setFont(u8g2_font_6x10_tf);
+  if (l1) g_oled.drawUTF8(0, 16, l1);
+  if (l2) g_oled.drawUTF8(0, 32, l2);
+  if (l3) g_oled.drawUTF8(0, 48, l3);
+  g_oled.sendBuffer();
+}