vaguely working all the embedded bits

Author: ArcaneNibble

firmware/.gdbinit

@@ -1,5 +1,5 @@
 tar ext /dev/cu.usbmodemDDC9D6D11
-mon tpwr en
+# mon tpwr en
 mon sw
 at 1
 set mem inaccessible-by-default off

firmware/led.c

@@ -1,6 +1,9 @@
 #include "led.h"
 #include "registers.h"
 
+uint32_t led_data[NUM_SECTORS];
+int led_current_sector;
+
 static inline void set_hi(int pin) {
     GPIOA_BSRR = 1 << pin;
     GPIOA_MODER &= ~(0b10 << (pin * 2));
@@ -48,10 +51,29 @@ const uint8_t led_pins[NUM_LEDS * 2] = {
     2, 3,
     3, 2,
 };
-void turn_on_led(int led) {
-    // make everything (relevant) tristate
-    GPIOA_MODER |= 0xfff;
+static inline void turn_on_led(int led) {
     // turn on *just* this LED
     set_hi(led_pins[led * 2 + 0]);
     set_lo(led_pins[led * 2 + 1]);
 }
+
+uint32_t current_led;
+void SysTick_Handler() {
+    uint32_t current_word = led_data[led_current_sector];
+
+    // turn off leds
+    GPIOA_MODER |= 0xfff;
+
+    if (current_word & (1 << current_led))
+        turn_on_led(current_led);
+
+    current_led++;
+    if (current_led == NUM_LEDS) {
+        current_led = 0;
+
+        // // test
+        // led_current_sector++;
+        // if (led_current_sector == NUM_SECTORS)
+        //     led_current_sector = 0;
+    }
+}

firmware/led.h

@@ -1,4 +1,8 @@
 #pragma once
+#include <stdint.h>
 
 #define NUM_LEDS 30
-void turn_on_led(int led);
+
+#define NUM_SECTORS 128
+extern uint32_t led_data[NUM_SECTORS];
+extern int led_current_sector;

firmware/main.c

@@ -5,7 +5,7 @@
 
 uint8_t debug_accel_whoami;
 uint8_t debug_accel_ctrl_readback[6];
-#define DEBUG_BUF_NENTS     1500
+#define DEBUG_BUF_NENTS     1200
 int16_t debug_accel_buffer[DEBUG_BUF_NENTS];
 uint32_t debug_accel_buffer_idx;
 
@@ -41,11 +41,22 @@ void main() {
     accel_write_reg(0x25, 0b00000000);
     accel_read_multi_reg(0x20, 6, debug_accel_ctrl_readback);
 
+    /// xxx dummy data
+    for (int i = 0; i < NUM_SECTORS; i++) {
+        led_data[i] = (1 << (i % (NUM_LEDS + 1))) - 1;
+    }
+
+    /// systick setup, 24 kHz = 30 LEDs * 400 Hz * 2x doubling
+    SYST_CVR = 0;
+    SYST_RVR = 999;
+    SYST_CSR = 0b111;
+
     /// PB3 = accel interrupt
     GPIOB_MODER &= ~(0b11 << 6);
     EXTI_EXTICR1 = 0b01 << 24;
     EXTI_RTSR = 1 << 3;
     EXTI_IMR |= 1 << 3;
+    NVIC_IPR1 = 0xc0 << 16;     // lower prio than led
 
     // initial read to make sure interrupt pin is cleared
     while (!(GPIOB_IDR & (1 << 3))) {}
@@ -76,10 +87,9 @@ void EXTI2_3_IRQHandler() {
 
     // maths!
     float angle = atan2f(-y, x);
-
-    float xxx_led_f = angle * 15.0f / (float)(M_PI);
-    int xxx_led = floorf(xxx_led_f);
-    if (xxx_led < 0)
-        xxx_led += 30;
-    turn_on_led(xxx_led);
+    float led_sector_f = angle * ((float)(NUM_SECTORS / 2) / (float)(M_PI));
+    int led_sector = floorf(led_sector_f);
+    if (led_sector < 0)
+        led_sector += NUM_SECTORS;
+    led_current_sector = led_sector;
 }

firmware/registers.h

@@ -91,6 +91,11 @@
 #define GPIOF_AFRH      (*(volatile uint32_t*)0x50001424)
 #define GPIOF_BRR       (*(volatile uint32_t*)0x50001428)
 
+#define SYST_CSR        (*(volatile uint32_t*)0xe000e010)
+#define SYST_RVR        (*(volatile uint32_t*)0xe000e014)
+#define SYST_CVR        (*(volatile uint32_t*)0xe000e018)
+#define SYST_CALIB      (*(volatile uint32_t*)0xe000e01c)
+
 #define NVIC_ISER       (*(volatile uint32_t*)0xe000e100)
 #define NVIC_ICER       (*(volatile uint32_t*)0xe000e180)
 #define NVIC_ISPR       (*(volatile uint32_t*)0xe000e200)
@@ -103,3 +108,11 @@
 #define NVIC_IPR5       (*(volatile uint32_t*)0xe000e414)
 #define NVIC_IPR6       (*(volatile uint32_t*)0xe000e418)
 #define NVIC_IPR7       (*(volatile uint32_t*)0xe000e41c)
+
+#define SCB_CPUID       (*(volatile uint32_t*)0xe000ed00)
+#define SCB_ICSR        (*(volatile uint32_t*)0xe000ed04)
+#define SCB_AIRCR       (*(volatile uint32_t*)0xe000ed0c)
+#define SCB_SCR         (*(volatile uint32_t*)0xe000ed10)
+#define SCB_CCR         (*(volatile uint32_t*)0xe000ed14)
+#define SCB_SHPR2       (*(volatile uint32_t*)0xe000ed1c)
+#define SCB_SHPR3       (*(volatile uint32_t*)0xe000ed20)