ignore accelerometer if it isn't found

CH58x/CH59x only has one main system clock and all timers are referenced to this clock. Other than watchdog, there's only one timer that runs independently: RTC. Thankfully the RTC has a mode to interrupt at rates faster than one second. this is being used for the program tick interrupt.

Also added OLED initialization code since that was forgotten before.

nametag8_CH592/StdPeriphDriver/CH59x_clk.c

@@ -562,7 +562,7 @@ void RTC_TRIGFunCfg(uint32_t cyc)
  *
  * @return  none
  */
-void RTC_ModeFunDisable(RTC_MODETypeDef m)
+void RTC_TRIGFunDisable(RTC_MODETypeDef m)
 {
     uint8_t i = 0;
 

nametag8_CH592/StdPeriphDriver/inc/CH59x_clk.h

@@ -260,7 +260,7 @@ void RTC_TMRFunCfg(RTC_TMRCycTypeDef t);
  *
  * @param   m   - 需要关闭的当前模式
  */
-void RTC_ModeFunDisable(RTC_MODETypeDef m);
+void RTC_TRIGFunDisable(RTC_MODETypeDef m);
 
 /**
  * @brief   获取RTC中断标志

nametag8_CH592/user/main.c

@@ -49,6 +49,8 @@
 #define FLAG_OLED_UPDATE        (1 << 0)
 #define FLAG_RGBLED_RUN_PROG    (1 << 1)
 
+#define PROG_TICK_RATE          (32768 / 256)
+
 
 
 const uint8_t vers[] = "241015a";
@@ -72,17 +74,43 @@ static uint8_t oled_tick = 0;           // oled framerate counter
 
 
 
-
-
 void ch59x_xtal_conf()
 {
     HSECFG_Current(HSE_RCur_125);
     HSECFG_Capacitance(HSECap_14p);
 }
 
-void systick_init()
+/*
+ * the CPU will change clockspeed depending on what it is doing.
+ * all timers are tied to system clock and cannot be derived from the crystal directly,
+ * except for RTC which can use the LSI. RTC also has a neat feature where it can
+ * trigger an interrupt when bits match a mask. at this time we're not using the RTC
+ * for anything else so putting RTC should suffice for our main tick interrupt.
+ */
+void rtc_reset_trig()
 {
+    sys_safe_access_enable();
+    R8_RTC_FLAG_CTRL |= RB_RTC_TRIG_CLR;
 
+    R32_RTC_TRIG = 0;
+    R8_RTC_MODE_CTRL |= RB_RTC_LOAD_HI;
+    sys_safe_access_disable();
+    while((R32_RTC_TRIG & 0x3FFF) != (R32_RTC_CNT_DAY & 0x3FFF));
+    sys_safe_access_enable();
+    R32_RTC_TRIG = 0;
+    R8_RTC_MODE_CTRL |= RB_RTC_LOAD_LO;
+    sys_safe_access_disable();
+
+    RTC_TRIGFunCfg(PROG_TICK_RATE);
+}
+
+void rtcisr_init()
+{
+    LClk32K_Cfg(Clk32K_LSI, ENABLE);                // enable internal oscillator
+    Calibration_LSI(Level_128);                     // calibrate LSI fromm HSE
+
+    rtc_reset_trig();
+    PFIC_EnableIRQ(RTC_IRQn);
 }
 
 void oled_update_done()
@@ -170,6 +198,7 @@ int main()
     // configure clock
     ch59x_xtal_conf();
     SetSysClock(SYSCLK_FREQ_USEI2C);
+    // note that system clock speed is decreased after every use of I2C.
 
     // enable DC-DC converter; brings significant power saving
     PWR_DCDCCfg(ENABLE);
@@ -199,10 +228,12 @@ int main()
     // configure port-based interrupts (used for ch32sub interrupt)
     port_intr_init();
 
-    // note that system clock speed is decreased after every use of I2C.
+    // start up the OLED
+    ssd1306fb_set_target(&oled);
+    ssd1306_init(1);    // we'll try to init later too, since sometimes they fail
 
-    // configure system tick
-    systick_init();
+    // configure main program tick interrupt
+    rtcisr_init();
 
     while(1) {
         // sleep when we're doing nothing
@@ -242,8 +273,13 @@ int main()
 }
 
 
-void SysTick_Handler(void)
+__INTERRUPT
+__HIGH_CODE
+void RTC_IRQHandler(void)
 {
+    // clear interrupt flag and reset RTC
+    rtc_reset_trig();
+
     st_tick++;
 
     if (!st_tick) {
@@ -276,7 +312,7 @@ void SysTick_Handler(void)
         }
     }
 
-    // read accelerometer data
+    // read accelerometer data at 32Hz
     if ((st_tick & 0x7) == 0x7) {
         accel_poll();
     }

nametag8_CH592/user/misc/accel.c

@@ -19,6 +19,7 @@
 // user data
 AccelData accel;
 
+uint8_t accel_found = 0;
 int16_t movement;
 
 
@@ -27,6 +28,7 @@ static stmdev_ctx_t dev_ctx;
 
 
 
+
 int32_t accel_i2c_write(void *handle, uint8_t reg, const uint8_t *bufp, uint16_t len)
 {
     (void)(handle);
@@ -50,40 +52,47 @@ void accel_init()
 {
     uint8_t devid;
     uint8_t reset;
+    uint16_t timeout = 1000;
 
     dev_ctx.write_reg = accel_i2c_write;
     dev_ctx.read_reg = accel_i2c_read;
 
     // make sure we've got the right device
     lis2dw12_device_id_get(&dev_ctx, &devid);
-    if (devid != LIS2DW12_ID) {
-        while (1) {
-            // might as well crash the user's badge
-        }
+    if (devid == LIS2DW12_ID) {
+        accel_found = 1;
     }
 
     // reset accelerometer
-    lis2dw12_reset_set(&dev_ctx, PROPERTY_ENABLE);
-    do {
-        lis2dw12_reset_get(&dev_ctx, &reset);
-    } while (reset);
+    if (accel_found) {
+        lis2dw12_reset_set(&dev_ctx, PROPERTY_ENABLE);
+        do {
+            lis2dw12_reset_get(&dev_ctx, &reset);
+            if (!reset) {
+                timeout = 0;
+                accel_found = 1;
+            }
+        } while (timeout);
+    }
 
-    // disable block update
-    // data in output registers is updated immediately; FIFO is disabled
-    lis2dw12_block_data_update_set(&dev_ctx, PROPERTY_DISABLE);
+    if (accel_found) {
+        // disable block update
+        // data in output registers is updated immediately; FIFO is disabled
+        lis2dw12_block_data_update_set(&dev_ctx, PROPERTY_DISABLE);
 
-    // configure scale, power mode
-    lis2dw12_full_scale_set(&dev_ctx, LIS2DW12_2g);
-    lis2dw12_power_mode_set(&dev_ctx, LIS2DW12_CONT_LOW_PWR_LOW_NOISE_4);
+        // configure scale, power mode
+        lis2dw12_full_scale_set(&dev_ctx, LIS2DW12_2g);
+        lis2dw12_power_mode_set(&dev_ctx, LIS2DW12_CONT_LOW_PWR_LOW_NOISE_4);
 
-    // configure filter chain
-    // low pass filter enabled for 6D (not currently used)
-    lis2dw12_filter_path_set(&dev_ctx, LIS2DW12_LPF_ON_OUT);
-    // digital LPF2 filter of output data
-    lis2dw12_filter_bandwidth_set(&dev_ctx, LIS2DW12_ODR_DIV_4);
+        // configure filter chain
+        // low pass filter enabled for 6D (not currently used)
+        lis2dw12_filter_path_set(&dev_ctx, LIS2DW12_LPF_ON_OUT);
+        // digital LPF2 filter of output data
+        lis2dw12_filter_bandwidth_set(&dev_ctx, LIS2DW12_ODR_DIV_4);
 
-    // configure output data rate
-    lis2dw12_data_rate_set(&dev_ctx, LIS2DW12_XL_ODR_200Hz);
+        // configure output data rate
+        lis2dw12_data_rate_set(&dev_ctx, LIS2DW12_XL_ODR_200Hz);
+    }
 }
 
 void accel_poll()
@@ -91,6 +100,8 @@ void accel_poll()
     uint8_t reg = 1;
     uint16_t xyz[3];
 
+    if (!accel_found) return;
+
     while (reg) {
         // read output only if new value is available
         lis2dw12_flag_data_ready_get(&dev_ctx, &reg);

nametag8_CH592/user/misc/accel.h

@@ -27,6 +27,8 @@ typedef struct AccelData {
 
 
 extern AccelData accel;
+
+extern uint8_t accel_found;
 extern uint16_t movement_worst;