From bc300e522ac161b141a2c094034f17ad4f370db4 Mon Sep 17 00:00:00 2001
From: true <true_git@truecontrol.org>
Date: Thu, 24 Oct 2024 17:22:20 -0700
Subject: [PATCH] main program tick interrupt now works

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    |  2 +-
 .../StdPeriphDriver/inc/CH59x_clk.h           |  2 +-
 nametag8_CH592/user/main.c                    | 52 ++++++++++++++++---
 3 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/nametag8_CH592/StdPeriphDriver/CH59x_clk.c b/nametag8_CH592/StdPeriphDriver/CH59x_clk.c
index b588663..cc88507 100644
--- a/nametag8_CH592/StdPeriphDriver/CH59x_clk.c
+++ b/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;
 
diff --git a/nametag8_CH592/StdPeriphDriver/inc/CH59x_clk.h b/nametag8_CH592/StdPeriphDriver/inc/CH59x_clk.h
index d70593f..c2a8e1b 100644
--- a/nametag8_CH592/StdPeriphDriver/inc/CH59x_clk.h
+++ b/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
diff --git a/nametag8_CH592/user/main.c b/nametag8_CH592/user/main.c
index 243a2a7..df91198 100644
--- a/nametag8_CH592/user/main.c
+++ b/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();
     }