From: Nils Faerber <nils.faerber@kernelconcepts.de>
Date: Sun, 5 May 2013 21:22:33 +0000 (+0200)
Subject: Make accelerometer work, interrup driven tilt change mode
X-Git-Url: https://git.karo-electronics.de/?p=oswald.git;a=commitdiff_plain;h=133faed023f55592a87ee1b8dbc74bc4a8917006

Make accelerometer work, interrup driven tilt change mode
---

diff --git a/metawatch/mw_acc.c b/metawatch/mw_acc.c
index 270f246..9c4b0f5 100644
--- a/metawatch/mw_acc.c
+++ b/metawatch/mw_acc.c
@@ -1,12 +1,87 @@
 #include <msp430.h>
 #include <msp430xgeneric.h>
 #include <stdint.h>
+#include <stdio.h>
 
 #include "mw_main.h"
+#include "mw_uart.h"
 
 #include "mw_acc.h"
 
-void mw_init_acc_i2c(void)
+#include "oswald_main.h"
+
+#define ACCEL_STATE_DISABLED		0x00
+#define ACCEL_STATE_ENABLED		0x01
+
+static uint8_t AccelState;
+static uint8_t AccelerometerBusy;
+static uint8_t LengthCount;
+static uint8_t Index;
+static uint8_t *pAccelerometerData;
+
+/*
+ * Accelerometer is a Kionix KXTF9-4100 connected to I2C
+ * I2C is pretty slow so reading and writing should be done non blocking
+ * using interrupts.
+ */
+
+#define ACCELEROMETER_NO_INTERRUPTS	0x00
+#define ACCELEROMETER_ALIFG		0x02
+#define ACCELEROMETER_NACKIFG		0x04
+#define ACCELEROMETER_STTIFG		0x06
+#define ACCELEROMETER_STPIFG		0x08
+#define ACCELEROMETER_RXIFG		0x0a
+#define ACCELEROMETER_TXIFG		0x0c
+
+#pragma vector=USCI_B1_VECTOR
+__interrupt void ACCERLEROMETER_I2C_ISR(void)
+{
+	// debug_uart_tx("ACC i2c irq\n");
+	switch (USCI_ACCELEROMETER_IV) {
+		case ACCELEROMETER_NO_INTERRUPTS: 
+			break;
+		case ACCELEROMETER_ALIFG: 
+			break;
+		case ACCELEROMETER_NACKIFG:
+			nop();
+			break; 
+		case ACCELEROMETER_STTIFG:
+			nop();
+			break; 
+		case ACCELEROMETER_STPIFG: 
+			break;
+		case ACCELEROMETER_RXIFG:
+			if (LengthCount > 0) {
+				pAccelerometerData[Index++] = ACCELEROMETER_RXBUF;
+				LengthCount--;
+				if ( LengthCount == 1 ) {
+					/* All but one byte received. Send stop */
+					ACCELEROMETER_CTL1 |= UCTXSTP;
+				} else if ( LengthCount == 0 ) {
+					/* Last byte received; disable rx interrupt */
+					ACCELEROMETER_IE &= ~UCRXIE;
+					AccelerometerBusy = 0;
+				}
+			}
+			break;
+		case ACCELEROMETER_TXIFG:
+			if ( LengthCount > 0 ) {
+				ACCELEROMETER_TXBUF = pAccelerometerData[Index++];
+				LengthCount--;
+			} else {
+				/* disable transmit interrupt and send stop */
+				ACCELEROMETER_IE &= ~UCTXIE;
+				ACCELEROMETER_CTL1 |= UCTXSTP;
+				AccelerometerBusy = 0;
+			}
+			break;
+		default:
+			break;
+	}
+
+}
+
+void mw_acc_init_i2c(void)
 {
 	/* enable reset before configuration */
 	ACCELEROMETER_CTL1 |= UCSWRST;
@@ -23,49 +98,307 @@ void mw_init_acc_i2c(void)
 	ACCELEROMETER_CTL1 &= ~UCSWRST;
 }
 
-/*
- * DMA2 = SPI for LCD
- */
-static void mw_acc_i2c_write_byte(uint8_t byte)
+void mw_acc_disable_i2c(void)
 {
-	ACCELEROMETER_TXBUF = byte;
-	while ((ACCELEROMETER_CTL1 & ACCELEROMETER_IFG) == 0)
-		nop();
+	/* enable reset to hold it */
+	ACCELEROMETER_CTL1 |= UCSWRST;
 }
 
-/* OK this is polling write, but data is small and 400kHz I2C, it should "just work" :) */
-void mw_acc_i2c_write(const uint8_t addr, const void *data, const uint8_t len)
+void mw_acc_i2c_write(uint8_t RegisterAddress, uint8_t *pData, uint8_t Length)
 {
-	int i;
-
-	if (len == 0) {
+	if (Length == 0 || pData == 0)
 		return;  
-	}
   
 	while (UCB1STAT & UCBBUSY)
 		nop();
   
+	AccelerometerBusy = 1;
+	LengthCount = Length;
+	Index = 0;
+	pAccelerometerData = pData;
+  
 	/* 
+	 * enable transmit interrupt and 
 	 * setup for write and send the start condition
 	 */
 	ACCELEROMETER_IFG = 0;
 	ACCELEROMETER_CTL1 |= UCTR + UCTXSTT;
-	while (!(ACCELEROMETER_IFG & UCTXIFG))
+	while(!(ACCELEROMETER_IFG & UCTXIFG))
 		nop();
   
 	/* 
-	 * clear transmit interrupt flag,
+	 * clear transmit interrupt flag, enable interrupt, 
 	 * send the register address
 	 */
 	ACCELEROMETER_IFG = 0;
+	ACCELEROMETER_IE |= UCTXIE;
+	ACCELEROMETER_TXBUF = RegisterAddress;
 
-	mw_acc_i2c_write_byte(addr);
+	while (AccelerometerBusy)
+		nop();
+
+	while (ACCELEROMETER_CTL1 & UCTXSTP)
+		nop();
 
-	for (i=0; i<len; i++)
-		mw_acc_i2c_write_byte(*(uint8_t *)(data+i));
+	/* the rest of TX will be handled by the ISR */
+}
 
+void mw_acc_i2c_read_single(const uint8_t RegisterAddress, const uint8_t *pData)
+{
+	if ( pData == 0 )
+		return;
+  
+	/* wait for bus to be free */
+	while (UCB1STAT & UCBBUSY)
+		nop();
+  
+	AccelerometerBusy = 1;
+	LengthCount = 1;
+	Index = 0;
+	pAccelerometerData = (uint8_t *)pData;
+
+	/* transmit address */
+	ACCELEROMETER_IFG = 0;
+	ACCELEROMETER_CTL1 |= UCTR + UCTXSTT;
+	while (!(ACCELEROMETER_IFG & UCTXIFG))
+		nop();
+  
+	/* write register address */
+	ACCELEROMETER_IFG = 0;
+	ACCELEROMETER_TXBUF = RegisterAddress;
+	while (!(ACCELEROMETER_IFG & UCTXIFG))
+		nop();
+
+	/* send a repeated start (same slave address now it is a read command) 
+	 * read possible extra character from rxbuffer
+	 */
+	ACCELEROMETER_RXBUF;
+	ACCELEROMETER_IFG = 0;
+	ACCELEROMETER_IE |= UCRXIE;
+	ACCELEROMETER_CTL1 &= ~UCTR;
+	/* for a read of a single byte the stop must be sent while the byte is being 
+	 * received. If this is interrupted an extra byte may be read.
+	 * however, it will be discarded during the next read
+	 */
+	if ( LengthCount == 1 ) {
+		/* errata usci30: prevent interruption of sending stop 
+		 * so that only one byte is read
+		 * this requires 62 us @ 320 kHz, 51 @ 400 kHz
+		 */
+		ACCELEROMETER_CTL1 |= UCTXSTT;
+  
+		while(ACCELEROMETER_CTL1 & UCTXSTT)
+			nop();
+
+		ACCELEROMETER_CTL1 |= UCTXSTP;
+	} else {
+		ACCELEROMETER_CTL1 |= UCTXSTT;
+	}
+  
+	/* wait until all data has been received and the stop bit has been sent */
+	while (AccelerometerBusy)
+		nop();
 	while (ACCELEROMETER_CTL1 & UCTXSTP)
 		nop();
+	Index = 0;
+	pAccelerometerData = 0;
 }
 
+/* errata usci30: only perform single reads 
+ * second solution: use DMA
+ */
+void mw_acc_i2c_read(const uint8_t RegisterAddress, uint8_t *pData, const uint8_t Length)
+{
+	int i;
+
+	for ( i = 0; i < Length; i++ ) {
+		mw_acc_i2c_read_single(RegisterAddress + i, (pData + i));
+	}
+}
+
+
+void mw_acc_init(void)
+{
+	uint8_t WriteRegisterData;
+	uint8_t pReadRegisterData[4];
+#if defined MW_DEVBOARD_V2
+	char tstr[16];
+#endif
+
+	ENABLE_ACCELEROMETER_POWER();
+
+	mw_acc_init_i2c();
+
+	/*
+	 * make sure part is in standby mode because some registers can only
+	 * be changed when the part is not active.
+	 */
+	WriteRegisterData = PC1_STANDBY_MODE;
+	mw_acc_i2c_write(KIONIX_CTRL_REG1, &WriteRegisterData, 1);
+
+	/* enable face-up and face-down detection */
+	WriteRegisterData = TILT_FDM | TILT_FUM;
+	mw_acc_i2c_write(KIONIX_CTRL_REG2, &WriteRegisterData, 1);
+    
+	/* 
+	 * the interrupt from the accelerometer can be used to get periodic data
+	 * the real time clock can also be used
+	 */
+  
+	/* change to output data rate to 25 Hz */
+	WriteRegisterData = WUF_ODR_25HZ | TAP_ODR_400HZ;
+	mw_acc_i2c_write(KIONIX_CTRL_REG3, &WriteRegisterData, 1);
+  
+	/* enable interrupt and make it active high */
+	WriteRegisterData = IEN | IEA;
+	mw_acc_i2c_write(KIONIX_INT_CTRL_REG1, &WriteRegisterData, 1);
+  
+	/* enable motion detection interrupt for all three axis */
+	WriteRegisterData = XBW | YBW | ZBW;
+	mw_acc_i2c_write(KIONIX_INT_CTRL_REG2, &WriteRegisterData, 1);
+
+	/* enable tap interrupt for Z-axis */
+	WriteRegisterData = TFDM;
+	mw_acc_i2c_write(KIONIX_INT_CTRL_REG3, &WriteRegisterData, 1);
+  
+	/* set TDT_TIMER to 0.2 secs*/
+	WriteRegisterData = 0x50;
+	mw_acc_i2c_write(KIONIX_TDT_TIMER, &WriteRegisterData, 1);
+  
+	/* set tap low and high thresholds (default: 26 and 182) */
+	WriteRegisterData = 40; //78;
+	mw_acc_i2c_write(KIONIX_TDT_L_THRESH, &WriteRegisterData, 1);
+	WriteRegisterData = 128;
+	mw_acc_i2c_write(KIONIX_TDT_H_THRESH, &WriteRegisterData, 1);
+    
+	/* set WUF_TIMER counter */
+	WriteRegisterData = 10;
+	mw_acc_i2c_write(KIONIX_WUF_TIMER, &WriteRegisterData, 1);
+    
+	/* this causes data to always be sent */
+	// WriteRegisterData = 0x00;
+	WriteRegisterData = 0x02 /*0x08*/;
+	mw_acc_i2c_write(KIONIX_WUF_THRESH, &WriteRegisterData, 1);
+     
+	/* single byte read test */
+	mw_acc_i2c_read(KIONIX_DCST_RESP, pReadRegisterData, 1);
+#if defined MW_DEVBOARD_V2
+	snprintf(tstr, 16, "acc DCST 0x%02x\n", pReadRegisterData[0]);
+	debug_uart_tx(tstr);
+#endif
+  
+	/* multiple byte read test */
+	mw_acc_i2c_read(KIONIX_WHO_AM_I, pReadRegisterData, 2);
+#if defined MW_DEVBOARD_V2
+	snprintf(tstr, 16, "acc is 0x%02x 0x%02x\n", pReadRegisterData[0], pReadRegisterData[1]);
+	debug_uart_tx(tstr);
+#endif
+
+	/* 
+	 * KIONIX_CTRL_REG3 and DATA_CTRL_REG can remain at their default values 
+	 *
+	 * 50 Hz
+	 */
+#if 0  
+	/* KTXF9 300 uA; KTXI9 165 uA */
+	WriteRegisterData = PC1_OPERATING_MODE | TAP_ENABLE_TDTE;
+  
+	/* 180 uA; KTXI9 115 uA */
+	WriteRegisterData = PC1_OPERATING_MODE | RESOLUTION_8BIT | WUF_ENABLE;
+
+	/* 180 uA; KTXI9 8.7 uA */
+	WriteRegisterData = PC1_OPERATING_MODE | TILT_ENABLE_TPE;
+
+	/* 720 uA; KTXI9 330 uA */  
+	WriteRegisterData = PC1_OPERATING_MODE | RESOLUTION_12BIT | WUF_ENABLE;
+#endif
+  
+	/* setup the default for the AccelerometerEnable command */
+#if 0
+	OperatingModeRegister = PC1_OPERATING_MODE | RESOLUTION_12BIT | TAP_ENABLE_TDTE | TILT_ENABLE_TPE; // | WUF_ENABLE;
+	InterruptControl = INTERRUPT_CONTROL_DISABLE_INTERRUPT;
+	SidControl = SID_CONTROL_SEND_DATA;
+	SidAddr = KIONIX_XOUT_L;
+	SidLength = XYZ_DATA_LENGTH;  
+
+	AccelState = ACCEL_STATE_INIT;
+#endif
+}
+
+void mw_acc_enable(void)
+{
+	uint8_t sdata;
+
+	mw_acc_init();
+
+	sdata = PC1_OPERATING_MODE | RESOLUTION_12BIT | TAP_ENABLE_TDTE | TILT_ENABLE_TPE | WUF_ENABLE;
+	//sdata = PC1_OPERATING_MODE | RESOLUTION_8BIT | TAP_ENABLE_TDTE | TILT_ENABLE_TPE; // | WUF_ENABLE;
+	mw_acc_i2c_write(KIONIX_CTRL_REG1, &sdata, 1);
+  
+	ACCELEROMETER_INT_ENABLE();
+	mw_acc_i2c_read(KIONIX_INT_REL, &sdata, 1);
+	AccelState = ACCEL_STATE_ENABLED;
+}
+
+void mw_acc_disable(void)
+{
+	uint8_t sdata;
+
+	if (AccelState == ACCEL_STATE_ENABLED) {
+		sdata = PC1_STANDBY_MODE;
+		mw_acc_i2c_write(KIONIX_CTRL_REG1, &sdata, 1);
+
+		ACCELEROMETER_INT_DISABLE();
+		mw_acc_disable_i2c();
+		DISABLE_ACCELEROMETER_POWER();
+		AccelState = ACCEL_STATE_DISABLED;
+	}
+}
+
+void mw_acc_read(int16_t *x, int16_t *y, int16_t *z)
+{
+	uint8_t rdata[6];
+
+	if (AccelState == ACCEL_STATE_ENABLED) {
+		mw_acc_i2c_read(KIONIX_XOUT_L, rdata, 6);
+
+		*x = rdata[0] | (rdata[1] << 8);
+		*y = rdata[2] | (rdata[3] << 8);
+		*z = rdata[4] | (rdata[5] << 8);
+	} else {
+		*x = 0;
+		*y = 0;
+		*z = 0;
+	}
+}
+
+void mw_acc_handle_irq(void)
+{
+	uint8_t sdata, srcreg1, srcreg2;
+#if defined MW_DEVBOARD_V2
+	char tstr[16];
+#endif
+
+	mw_acc_i2c_read(KIONIX_INT_SRC_REG1, &srcreg1, 1);
+#if defined MW_DEVBOARD_V2
+	snprintf(tstr, 16, "accsrc1: 0x%02x\n", srcreg1);
+	debug_uart_tx(tstr);
+#endif
+	mw_acc_i2c_read(KIONIX_INT_SRC_REG2, &srcreg2, 1);
+#if defined MW_DEVBOARD_V2
+	snprintf(tstr, 16, "accsrc2: 0x%02x\n", srcreg2);
+	debug_uart_tx(tstr);
+#endif
+	if (srcreg1 & INT_TAP_SINGLE) {
+	};
+	if (srcreg1 & INT_TAP_DOUBLE) {
+	};
+	if (srcreg2 & INT_WUFS) {
+		int16_t x, y, z;
+		mw_acc_read(&x, &y, &z);
+		oswald_handle_accel_event((int8_t)(x / (32768 / 255)), (int8_t)(y / (32768 / 255)), (int8_t)(z / (32768 / 255)));
+	}
+
+	mw_acc_i2c_read(KIONIX_INT_REL, &sdata, 1);
+}
 
diff --git a/metawatch/mw_acc.h b/metawatch/mw_acc.h
index 59cee93..2acf7c7 100644
--- a/metawatch/mw_acc.h
+++ b/metawatch/mw_acc.h
@@ -99,11 +99,22 @@
 #define TFUM (1 << 0)
 
 /* INT_SRC_REG2 */
-#define INT_TAP_SINGLE (0x04)
-#define INT_TAP_DOUBLE (0x08)
+#define INT_TPS		0x01
+#define INT_WUFS	0x02
+#define INT_TAP_SINGLE	0x04
+#define INT_TAP_DOUBLE	0x08
+#define INT_DRDY	0x10
 
-/* for readability */
-#define ONE_BYTE ( 1 )
 
-#endif
+void mw_acc_init_i2c(void);
+void mw_acc_disable_i2c(void);
+void mw_acc_i2c_read(const uint8_t RegisterAddress, uint8_t *pData, const uint8_t Length);
+void mw_acc_i2c_write(uint8_t RegisterAddress, uint8_t *pData, uint8_t Length);
+
+void mw_acc_init(void);
+void mw_acc_enable(void);
+void mw_acc_disable(void);
+void mw_acc_read(int16_t *x, int16_t *y, int16_t *z);
+void mw_acc_handle_irq(void);
 
+#endif
diff --git a/metawatch/mw_bt.c b/metawatch/mw_bt.c
index 7cb24e1..8138b1e 100644
--- a/metawatch/mw_bt.c
+++ b/metawatch/mw_bt.c
@@ -188,17 +188,6 @@ void mw_enable_bt(void)
 	mw_bt_enabled = 1;
 }
 
-#pragma vector=PORT1_VECTOR
-__interrupt void BT_CTS_ISR (void)
-{
-	P1IFG &= ~BT_IO_CTS;
-
-	debug_uart_tx("BTS CTS triggered\n");
-	bt_hci_ehcill_wake();
-
-	LPM3_EXIT;
-}
-
 void mw_disable_bt(void)
 {
 	mw_bt_enabled = 0;
diff --git a/metawatch/mw_main.c b/metawatch/mw_main.c
index 89b014e..4f8ee90 100644
--- a/metawatch/mw_main.c
+++ b/metawatch/mw_main.c
@@ -10,6 +10,7 @@
 #include "mw_bt.h"
 #include "mw_adc.h"
 #include "mw_bt.h"
+#include "mw_acc.h"
 #include "bt_hci.h"
 #include "bt_l2cap.h"
 
@@ -18,7 +19,7 @@
 
 #include "bluetooth_init_cc256x.h"
 
-unsigned int _event_src = 0;
+uint16_t _event_src = 0;
 
 
 static void set16mhz(void)
@@ -111,7 +112,7 @@ static void setup_pins(void)
 	DISABLE_LCD_LED();		// frontlight
 	CONFIG_DEBUG_PINS();
 	CONFIG_ACCELEROMETER_PINS();
-	// DISABLE_ACCELEROMETER_POWER(); // there is no accel. power switching!
+	DISABLE_ACCELEROMETER_POWER(); // starts from config 5 and later
 
 	HARDWARE_CFG_SENSE_INIT();
 
@@ -324,7 +325,19 @@ static void handle_uart_rx_event(void)
 
 	if (debug_uart_rx_char(&c)) {
 		debug_uart_tx_char(c);
-		if (c == 'b') {
+		if (c == 'a') {
+			debug_uart_tx("\nenabling ACC\n");
+			mw_acc_enable();
+		} else if (c == 'A') {
+			debug_uart_tx("\ndisabling ACC\n");
+			mw_acc_disable();
+		} else if (c == 'r') {
+			int16_t x,y,z;
+			debug_uart_tx("\nread ACC: ");
+			mw_acc_read(&x, &y, &z);
+			snprintf(tstr, 64, "x:%d y:%d z:%d\n", x,y,z);
+			debug_uart_tx(tstr);
+		} else if (c == 'b') {
 			debug_uart_tx("\nenabling BT\n");
 			mw_enable_bt();
 		} else if (c == 'B') {
@@ -484,6 +497,9 @@ uint8_t handle_event(void)
 		} else if (_event_src & TIMER_100MS_EVENT) {
 			_event_src &= ~TIMER_100MS_EVENT;
 			oswald_centisecond_tick();
+		} else if (_event_src & ACCEL_EVENT) {
+			_event_src &= ~ACCEL_EVENT;
+			mw_acc_handle_irq();
 		} else {
 #if defined MW_DEVBOARD_V2
 			snprintf(tstr, 64, "unhandled event in 0x%04x\n", _event_src);
@@ -504,6 +520,26 @@ __interrupt void BUTTON_ISR (void)
 	LPM3_EXIT;
 }
 
+#pragma vector=PORT1_VECTOR
+__interrupt void PORT1_GPIO_ISR (void)
+{
+	if (P1IFG & BT_IO_CTS) {
+		P1IFG &= ~BT_IO_CTS;
+
+		debug_uart_tx("BT CTS irq\n");
+		bt_hci_ehcill_wake();
+
+		LPM3_EXIT;
+	};
+	if (P1IFG & ACCELEROMETER_INT_PIN) {
+		P1IFG &= ~ACCELEROMETER_INT_PIN;
+		// debug_uart_tx("ACC irq\n");
+		_event_src |= ACCEL_EVENT;
+		LPM3_EXIT;
+	}
+}
+
+
 #if 0
 #pragma vector=NOVECTOR
 __interrupt void UNEXP_ISR (void)
diff --git a/metawatch/mw_main.h b/metawatch/mw_main.h
index 23dcf5e..039d402 100644
--- a/metawatch/mw_main.h
+++ b/metawatch/mw_main.h
@@ -21,6 +21,7 @@
 #define TIMER_100MS_EVENT	1 << 5
 #define POWER_SRC_EVENT		1 << 6
 #define BT_UART_RCV_EVENT	1 << 7
+#define ACCEL_EVENT		1 << 8
 
 extern unsigned int _event_src;
 
diff --git a/metawatch/oswald_hal.c b/metawatch/oswald_hal.c
index 449355d..528f1a6 100644
--- a/metawatch/oswald_hal.c
+++ b/metawatch/oswald_hal.c
@@ -14,6 +14,7 @@
 #include "bt_hci.h"
 #include "bt_l2cap.h"
 #include "bluetooth_init_cc256x.h"
+#include "mw_acc.h"
 
 #include "oswald.h"
 #include "oswald_hal.h"
@@ -249,3 +250,17 @@ void hal_bluetooth_send_data(const void *mdat, uint16_t mlen)
 	bt_l2cap_send_channel(0x40, mdat, mlen);
 }
 
+/*
+ * Control the accelerometer
+ */
+void hal_accelerometer_enable(void)
+{
+	mw_acc_enable();
+}
+
+void hal_accelerometer_disable(void)
+{
+	mw_acc_disable();
+}
+
+
diff --git a/ui/calendar.c b/ui/calendar.c
index 6271e12..feca174 100644
--- a/ui/calendar.c
+++ b/ui/calendar.c
@@ -4,9 +4,10 @@
 
 unsigned char is_leap(const unsigned int year)
 {
-  // Die Regel lautet: Alles, was durch 4 teilbar ist, ist ein Schaltjahr.
-  // Es sei denn, das Jahr ist durch 100 teilbar, dann ist es keins.
-  // Aber wenn es durch 400 teilbar ist, ist es doch wieder eins.
+	/* the rule is, everything that can be devided by 4 is leap.
+	 * Exception: the year can be devided by 100, then it is not,
+	 * except it canbe devided by 400, then it is again.
+	 */
 
 	if ((year % 400) == 0)
 		return 1;
@@ -20,11 +21,11 @@ unsigned char is_leap(const unsigned int year)
 
 unsigned short days_of_month(const unsigned int uMonat, const unsigned int uJahr)
 {
-	//                     ungült,Jan,Feb,Mrz,Apr,Mai,Jun,Jul,Aug,Sep,Okt,Nov,Dez
+	// invalid,January,Febuary,March,April,May,June,July,August,September,October,November,December
 	int arrTageImMonat[13] = {  0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
 	if (uMonat == 2) {
-		// Februar: Schaltjahr unterscheiden
+		// Febuary: distinguish leap
 		if (is_leap(uJahr))
 			return 29;
 		else
diff --git a/ui/oswald-ui.c b/ui/oswald-ui.c
index c482c78..29e15fd 100644
--- a/ui/oswald-ui.c
+++ b/ui/oswald-ui.c
@@ -109,6 +109,22 @@ const char *hal_get_radio_version_string(void)
 	return "BlueZ";
 }
 
+void hal_accelerometer_enable(void)
+{
+	g_printerr("accel enable\n");
+	gtk_widget_set_sensitive(ui_g->x_sc, TRUE);
+	gtk_widget_set_sensitive(ui_g->y_sc, TRUE);
+	gtk_widget_set_sensitive(ui_g->z_sc, TRUE);
+}
+
+void hal_accelerometer_disable(void)
+{
+	g_printerr("accel enable\n");
+	gtk_widget_set_sensitive(ui_g->x_sc, FALSE);
+	gtk_widget_set_sensitive(ui_g->y_sc, FALSE);
+	gtk_widget_set_sensitive(ui_g->z_sc, FALSE);
+}
+
 
 static gint
 configure_event (GtkWidget *widget, GdkEventConfigure *event, gpointer user_data)
@@ -330,18 +346,24 @@ static void create_mainwin(oswald_ui *ui)
 	sc = gtk_hscale_new_with_range (-128, 127, 1);
 	gtk_box_pack_start (GTK_BOX(hb), sc, TRUE, TRUE, 5);
 	g_signal_connect(G_OBJECT(sc), "value-changed", G_CALLBACK(accelX_value_changed), ui);
+	ui->x_sc = sc;
+	gtk_widget_set_sensitive(ui->x_sc, FALSE);
 
 	l = gtk_label_new("Y:");
 	gtk_box_pack_start (GTK_BOX(hb), l, FALSE, FALSE, 5);
 	sc = gtk_hscale_new_with_range (-128, 127, 1);
 	gtk_box_pack_start (GTK_BOX(hb), sc, TRUE, TRUE, 5);
 	g_signal_connect(G_OBJECT(sc), "value-changed", G_CALLBACK(accelY_value_changed), ui);
+	ui->y_sc = sc;
+	gtk_widget_set_sensitive(ui->y_sc, FALSE);
 
 	l = gtk_label_new("Z:");
 	gtk_box_pack_start (GTK_BOX(hb), l, FALSE, FALSE, 5);
 	sc = gtk_hscale_new_with_range (-128, 127, 1);
 	gtk_box_pack_start (GTK_BOX(hb), sc, TRUE, TRUE, 5);
 	g_signal_connect(G_OBJECT(sc), "value-changed", G_CALLBACK(accelZ_value_changed), ui);
+	ui->z_sc = sc;
+	gtk_widget_set_sensitive(ui->z_sc, FALSE);
 
 	gtk_widget_show_all(ui->mainwin);
 }
diff --git a/ui/oswald-ui.h b/ui/oswald-ui.h
index 0872a94..fdadd4b 100644
--- a/ui/oswald-ui.h
+++ b/ui/oswald-ui.h
@@ -9,6 +9,9 @@ typedef struct {
 	GtkWidget *mainwin;
 	GtkWidget *darea;
 	GdkPixmap *pixmap;
+	GtkWidget *x_sc;
+	GtkWidget *y_sc;
+	GtkWidget *z_sc;
 	uint8_t accel_x;
 	uint8_t accel_y;
 	uint8_t accel_z;
diff --git a/ui/oswald_hal.h b/ui/oswald_hal.h
index ad877d0..bc7a715 100644
--- a/ui/oswald_hal.h
+++ b/ui/oswald_hal.h
@@ -36,5 +36,9 @@ uint8_t *hal_bluetooth_get_local_bdaddr(void);
 void hal_bluetooth_set_visible(boolean visible);
 boolean hal_bluetooth_get_visible(void);
 void hal_bluetooth_send_data(const void *mdat, uint16_t mlen);
+
+void hal_accelerometer_enable(void);
+void hal_accelerometer_disable(void);
+
 #endif
 
diff --git a/ui/oswald_screens.c b/ui/oswald_screens.c
index 9952365..c079e44 100644
--- a/ui/oswald_screens.c
+++ b/ui/oswald_screens.c
@@ -143,6 +143,8 @@ static accelscreen_data_t accel_screen = {
 
 void draw_accel_screen(accel_data_t *accel_data)
 {
+	uint8_t x,y;
+
 	hal_lcd_clear_display();
 
 	oswald_draw_bitmap(36, 0, acc_icon_width, acc_icon_height, acc_icon_bits);
@@ -162,7 +164,13 @@ void draw_accel_screen(accel_data_t *accel_data)
 	oswald_draw_line(40, 82, 92, 82);
 	oswald_draw_line(40, 82, 40, 30);
 
-	oswald_draw_pixel(41+25+((accel_data->x * 50) / (254)), 31+25+((accel_data->y * 50) / (254)));
+	x = 41+25+((accel_data->x * 50) / (254));
+	y = 31+25+((accel_data->y * 50) / (254));
+	oswald_draw_pixel(x, y);
+	oswald_draw_pixel(x+1, y);
+	oswald_draw_pixel(x-1, y);
+	oswald_draw_pixel(x, y+1);
+	oswald_draw_pixel(x, y-1);
 
 	hal_lcd_update_display();
 }
@@ -172,6 +180,11 @@ event_ret_t accel_handle_events(uint16_t event, void *data)
 	switch (event) {
 		case EVENT_SCREEN_VISIBLE:
 			draw_accel_screen(&accel_screen.accdata);
+			hal_accelerometer_enable();
+			return EVENT_RET_HANDLED;
+			break;
+		case EVENT_SCREEN_DESTROY:
+			hal_accelerometer_disable();
 			return EVENT_RET_HANDLED;
 			break;
 		case EVENT_ACCEL_UPDATE: {