Add SC7A20 accelerometer support

!!! AI GENERATED MESSAGE !!!
This commit introduces support for the SC7A20 accelerometer.
The accelerometer readings can now be displayed on the screen,
and the display mode can be toggled using the encoder.
Additionally, the EMA filter constants for voltage and current
readings have been updated from K2 to K4 for potentially smoother
readings.

fw/Makefile

@@ -12,7 +12,7 @@ U8G2_SRC:=$(U8G2_DIR)/u8x8_d_$(DISPLAY).c $(filter-out $(U8G2_DIR)/u8x8_d_%.c, \
 	$(filter-out $(U8G2_DIR)/mui%.c, $(wildcard $(U8G2_DIR)/*.c)))
 
 EXTRA_CFLAGS += -I$(U8G2_DIR)
-ADDITIONAL_C_FILES += lib_i2c.c display.c
+ADDITIONAL_C_FILES += lib_i2c.c display.c sc7a20.c
 
 include ch32fun/ch32fun/ch32fun.mk
 

fw/filter.h

@@ -11,5 +11,10 @@
 #define U16_FP_EMA_K8(x, s)  (u16)((((u32)(x)<<8) - (x) + (s)) >> 8)
 #define U16_FP_EMA_K16(x, s) (u16)((((u32)(x)<<16) - (x) + (s)) >> 16)
 
+#define I16_FP_EMA_K2(x, s)  (s16)((((s32)(x)<<2) - (x) + (s)) >> 2)
+#define I16_FP_EMA_K4(x, s)  (s16)((((s32)(x)<<4) - (x) + (s)) >> 4)
+#define I16_FP_EMA_K8(x, s)  (s16)((((s32)(x)<<8) - (x) + (s)) >> 8)
+#define I16_FP_EMA_K16(x, s) (s16)((((s32)(x)<<16) - (x) + (s)) >> 16)
+
 
 #endif // _FILTER_H

fw/main.c

@@ -9,6 +9,7 @@
 #include "lib_i2c.h"
 #include "display.h"
 #include "filter.h"
+#include "sc7a20.h"
 
 
 // Pin definitions
@@ -324,6 +325,7 @@ __attribute__((noreturn)) int main(void)
 	Delay_Ms(500);
 
 	u8g2 = display_init();
+	sc7a20_init();
 
 	// Init USBPD
 	USBPD_VCC_e vcc = eUSBPD_VCC_3V3;
@@ -396,13 +398,13 @@ __attribute__((noreturn)) int main(void)
 
 		poll_input(); // usb
 
-		vbus_mv = U16_FP_EMA_K2(vbus_mv, ((u32)adc_buffer[0]*VCC_MV*11)/4096);
+		vbus_mv = U16_FP_EMA_K4(vbus_mv, ((u32)adc_buffer[0]*VCC_MV*11)/4096);
-		current_ma = U16_FP_EMA_K2(current_ma, get_current_ma(adc_buffer[1]));
+		current_ma = U16_FP_EMA_K4(current_ma, get_current_ma(adc_buffer[1]));
-		temp_k = U16_FP_EMA_K2(temp_k, get_temp_k(adc_buffer[2]));
+		temp_k = I16_FP_EMA_K4(temp_k, get_temp_k(adc_buffer[2]));
 		if (!adc_injection_conversion()) {
 		    printf("injection conversion failed");
 		} else {
-		    tip_mv = U16_FP_EMA_K2(tip_mv, (u32)(injection_results[0]*VCC_MV)/4096);
+		    tip_mv = U16_FP_EMA_K4(tip_mv, (u32)(injection_results[0]*VCC_MV)/4096);
 		}
 
 		u8g2_ClearBuffer(u8g2);
@@ -411,14 +413,26 @@ __attribute__((noreturn)) int main(void)
 		u8g2_SetFont(u8g2, u8g2_font_5x8_tr);
 #define x_off 0
 #define y_off 8
-		u8g2_DrawStr(u8g2, x_off+0, y_off+7, "TIP:");
+		static bool mode = true;
-		u8g2_DrawStr(u8g2, x_off+20, y_off+7, u8x8_u16toa(tip_mv, 4));
+		if (mode) {
-		u8g2_DrawStr(u8g2, x_off+0, y_off+15, "VBUS:");
+			u8g2_DrawStr(u8g2, x_off+0, y_off+7, "TIP:");
-		u8g2_DrawStr(u8g2, x_off+25, y_off+15, u8x8_u16toa(vbus_mv, 4));
+			u8g2_DrawStr(u8g2, x_off+20, y_off+7, u8x8_u16toa(tip_mv, 4));
-		u8g2_DrawStr(u8g2, x_off+51, y_off+7, "TEMP:");
+			u8g2_DrawStr(u8g2, x_off+0, y_off+15, "VBUS:");
-		u8g2_DrawStr(u8g2, x_off+75, y_off+7, u8x8_u16toa(temp_k, 2));
+			u8g2_DrawStr(u8g2, x_off+25, y_off+15, u8x8_u16toa(vbus_mv, 4));
-		u8g2_DrawStr(u8g2, x_off+51, y_off+15, "V:");
+			u8g2_DrawStr(u8g2, x_off+51, y_off+7, "TEMP:");
-		u8g2_DrawStr(u8g2, x_off+60, y_off+15, u8x8_u16toa(max_v, 2));
+			u8g2_DrawStr(u8g2, x_off+75, y_off+7, u8x8_u16toa(temp_k, 2));
+			u8g2_DrawStr(u8g2, x_off+51, y_off+15, "V:");
+			u8g2_DrawStr(u8g2, x_off+60, y_off+15, u8x8_u16toa(max_v, 2));
+		} else {
+			static int16_t ax, ay, az;
+			sc7a20_get_readings(&ax, &ay, &az);
+			u8g2_DrawStr(u8g2, x_off+0, y_off+7, ax > 0 ? "AX:+" : "AX:-");
+			u8g2_DrawStr(u8g2, x_off+20, y_off+7, u8x8_u16toa(ax > 0 ? ax : -ax, 5));
+			u8g2_DrawStr(u8g2, x_off+0, y_off+15, ay > 0 ? "AY:+" : "AY:-");
+			u8g2_DrawStr(u8g2, x_off+20, y_off+15, u8x8_u16toa(ay > 0 ? ay : -ay, 5));
+			u8g2_DrawStr(u8g2, x_off+50, y_off+7, az > 0 ? "AZ:+" : "AZ:-");
+			u8g2_DrawStr(u8g2, x_off+70, y_off+7, u8x8_u16toa(az > 0 ? az : -az, 5));
+		}
 
 		u8g2_SendBuffer(u8g2);
 
@@ -426,6 +440,10 @@ __attribute__((noreturn)) int main(void)
 			USBPD_SelectPDO(idx_9v, 0);
 			Delay_Ms(200);
 		}
+		if (encoder != 0) {
+			mode = !mode;
+			encoder = 0;
+		}
 
 //		printf("VBUS=%d, CURRENT=%d, TEMP=%d, TIP=%d, COUNTER=%d\n", vbus_mv, current_ma, temp_k, tip_mv, encoder);
 

fw/sc7a20.c

@@ -0,0 +1,54 @@
+#include <ch32fun.h>
+#include "lib_i2c.h"
+
+#include "sc7a20.h"
+
+
+// Initialization values for control registers, in reg-value pairs
+// Basically setup the unit to run, and enable 4D orientation detection
+// TODO: Make better comments and define values
+static const uint8_t i2c_registers[][2] = {
+    {    SC7A20_CTRL_REG1, 0b01100111}, // 200Hz, XYZ enabled
+    {    SC7A20_CTRL_REG2, 0b00000000}, // Setup filter to 0x00 ??
+    {    SC7A20_CTRL_REG3, 0b00000000}, // INT1 off
+    {    SC7A20_CTRL_REG4, 0b00001000}, // Block mode off,little-endian,2G,High-pres,self test off
+    {    SC7A20_CTRL_REG5, 0b00000100}, // fifo off, D4D on INT1
+    {    SC7A20_CTRL_REG6,       0x00}, // INT2 off
+    {     SC7A20_INT2_CFG, 0b01111110}, // setup for movement detection
+    {     SC7A20_INT2_THS,       0x28}, //
+    {SC7A20_INT2_DURATION,         64}, //
+    {     SC7A20_INT1_CFG, 0b01111110}, //
+    {     SC7A20_INT1_THS,       0x28}, //
+    {SC7A20_INT1_DURATION,         64}
+};
+
+
+void sc7a20_init()
+{
+	// Setup acceleration readings
+	// 2G range
+	// bandwidth = 250Hz
+	// High pass filter on (Slow compensation)
+	// Turn off IRQ output pins
+	// Orientation recognition in symmetrical mode
+	// Hysteresis is set to ~ 16 counts
+	// Theta blocking is set to 0b10
+	for (uint8_t i = 0; i < sizeof(i2c_registers) / sizeof(i2c_registers[0]); i++) {
+		uint8_t bytes[2] = {i2c_registers[i][0], i2c_registers[i][1]};
+		i2c_sendBytes(I2C_TARGET, SC7A20_ADDRESS, bytes, 2);
+	}
+}
+
+void sc7a20_get_readings(int16_t *x, int16_t *y, int16_t *z)
+{
+	// We can tell the accelerometer to output in LE mode which makes this simple
+	int16_t sensorData[3] = {0};
+
+	i2c_sendByte(I2C_TARGET, SC7A20_ADDRESS, SC7A20_OUT_X_L | 0x80);
+	i2c_readBytes(I2C_TARGET, SC7A20_ADDRESS, (u8*)sensorData, 6);
+
+	// Lower byte is sent first
+	*x = (int16_t)sensorData[0];
+	*y = (int16_t)sensorData[1];
+	*z = (int16_t)sensorData[2];
+}

fw/sc7a20.h

@@ -0,0 +1,56 @@
+/*
+ * SC7A20_defines.h
+ *
+ *  Created on: 18 Sep. 2020
+ *      Author: Ralim
+ */
+
+#ifndef _SC7A20_H_
+#define _SC7A20_H_
+
+#include <ch32fun.h>
+
+#define SC7A20_ADDRESS 0x18
+
+#define SC7A20_WHO_AM_I_VALUE (0b00010001)
+#define SC7A20_WHO_AMI_I      0x0F
+#define SC7A20_CTRL_REG1      0x20
+#define SC7A20_CTRL_REG2      0x21
+#define SC7A20_CTRL_REG3      0x22
+#define SC7A20_CTRL_REG4      0x23
+#define SC7A20_CTRL_REG5      0x24
+#define SC7A20_CTRL_REG6      0x25
+#define SC7A20_REFERENCE      0x26
+#define SC7A20_STATUS_REG     0x27
+#define SC7A20_OUT_X_L        0x28
+#define SC7A20_OUT_X_L_ALT    0xA8
+#define SC7A20_OUT_X_H        0x29
+#define SC7A20_OUT_Y_L        0x2A
+#define SC7A20_OUT_Y_H        0x2B
+#define SC7A20_OUT_Z_L        0x2C
+#define SC7A20_OUT_Z_H        0x2D
+#define SC7A20_FIFO_CTRL      0x2E
+#define SC7A20_FIFO_SRC       0x2F
+#define SC7A20_INT1_CFG       0x30
+#define SC7A20_INT1_SOURCE    0x31
+#define SC7A20_INT1_THS       0x32
+#define SC7A20_INT1_DURATION  0x33
+#define SC7A20_INT2_CFG       0x34
+#define SC7A20_INT2_SOURCE    0x35
+#define SC7A20_INT2_THS       0x36
+#define SC7A20_INT2_DURATION  0x37
+#define SC7A20_CLICK_CFG      0x38
+#define SC7A20_CLICK_SRC      0x39
+#define SC7A20_CLICK_THS      0x3A
+#define SC7A20_TIME_LIMIT     0x3B
+#define SC7A20_TIME_LATENCY   0x3C
+#define SC7A20_TIME_WINDOW    0x3D
+#define SC7A20_ACT_THS        0x3E
+#define SC7A20_ACT_DURATION   0x3F
+
+
+void sc7a20_init(void);
+void sc7a20_get_readings(int16_t *x, int16_t *y, int16_t *z);
+
+
+#endif /* CORE_DRIVERS_BMA223_DEFINES_H_ */