I2C hang recover function added

Dependencies:   UniGraphic mbed vt100

In this version, check_i2c_pins function was added in edge_mgr.cpp.

プログラムの起動時、I2Cモジュールを初期化する前に、I2Cに使用するピンの電位を確認し
もし一方でも Low に張り付いていた場合、SCL を GPIO 出力に設定して 
所定回数 (I2C_UNLOCK_TRIAL_CYCLE) 反転させることにより、疑似リセットクロックを生成します。

その後は、通常の起動手順に復帰し、以降はこれまでと同様の動作をします。

Revision:
0:d895cd1cd897
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sensors/LM75B.cpp	Tue Apr 03 08:30:29 2018 +0000
@@ -0,0 +1,122 @@
+#include "mbed.h"
+#include "LM75B.h"
+#include "af_mgr.h"
+
+/* Register list */
+#define PTR_CONF    0x01
+#define PTR_TEMP    0x00
+#define PTR_TOS     0x03
+#define PTR_THYST   0x02
+
+/* Configuration register */
+/* B[7:5] : Reserved */
+/* B[4:3] : OS_F_QUE[1:0] OS fault queue value */
+#define CONFIG_QUE_1    0x00
+#define CONFIG_QUE_2    (0x01 << 3)
+#define CONFIG_QUE_4    (0x10 << 3)
+#define CONFIG_QUE_6    (0x11 << 3) 
+/* B[2] : OS_POL  0 = OS active LOW,  1 = OS active HIGH */
+#define CONFIG_OS_POL_L 0x00
+#define CONFIG_OS_POL_H (0x01 << 2)
+/* B[1] : OS_COMP_INT 0 = OS comparator, 1 = OS interrupt */
+#define CONFIG_OS_COMP  0x00
+#define CONFIG_OS_INT   (0x01 << 1)
+/* B[0] : SHUTDOWN    0 = normal, 1 = shutdown */
+#define CONFIG_NORMARL  0x00
+#define CONFIG_SHUTDOWN 0x01
+
+/* Temperature register */
+/* D[15:5] = 11 bit data 0.125 * temp data */
+/* D[4:0] : reserved */
+
+/* Tos register */
+/* D[15:7] = 9 bit data */
+/* D[6:0] : reserved */
+
+/* Thyst register */
+/* D[15:7] = 9 ibt data */
+/* D[6:0] : reserved */
+
+LM75B::LM75B(I2C *i2c, int addr) : m_addr(addr<<1) {
+    p_i2c = i2c ;
+    p_i2c->frequency(100000); /* 100kHz */
+    // activate the peripheral
+}
+
+LM75B::~LM75B() { }
+
+int LM75B::temp(int8_t *temp)
+{
+    int result ;
+    char t[1] = { 0x00 } ;
+    result = p_i2c->write(m_addr, t, 1, true) ;
+    if (result == 0) {
+        result = p_i2c->read(m_addr, t, 1) ;
+    }
+    if (result == 0) {
+        *temp = (int8_t)t[0] ;
+    }
+    return( result ) ;
+}
+
+int LM75B::getTemp(float *temp)
+{
+    int result ;
+    char t[2] = { 0, 0 } ;
+    int16_t iTemp = 0 ;
+    result = p_i2c->write(m_addr, t, 1) ; /* write pointer byte 0x00 */
+    if (result == 0) {
+        result = p_i2c->read(m_addr, t, 2) ; /* read MSB, LSB */
+    }
+    if (result == 0) {
+        iTemp = (t[0] << 8) | t[1] ;
+        iTemp >>= 5 ;
+        *temp = 0.125 * iTemp ;
+    }
+    return( result ) ;
+}
+
+int LM75B::getConfig(uint8_t ptr_byte, uint8_t *config_data) 
+{
+    int result ;
+    char config = 0x00 ; /* default value */
+    result = p_i2c->write(m_addr, (char*)(&ptr_byte), 1, true) ;
+    if (result == 0) {
+        result = p_i2c->read(m_addr, &config, 1) ;
+    }
+    if (result == 0) {
+        *config_data = config ;
+    }
+    return( result ) ;
+}
+
+int LM75B::setConfig(uint8_t ptr_byte, uint8_t config_data) 
+{
+    int result ;
+    char t[2] ;
+    t[0] = ptr_byte ;
+    t[1] = config_data ;
+    result = p_i2c->write(m_addr, t, 2, true) ;
+    return( result ) ;
+}
+
+int LM75B::readRegs(int addr, uint8_t * data, int len) 
+{
+    int result ;
+    char t[1] = {addr};
+    __disable_irq() ; // Disable Interrupts
+    result = p_i2c->write(m_addr, t, 1, true);
+    if (result == 0) {
+        result = p_i2c->read(m_addr, (char *)data, len);
+    }
+    __enable_irq() ; // Enable Interrupts
+    return( result ) ;
+}
+
+int LM75B::writeRegs(uint8_t * data, int len) {
+    int result ;
+    __disable_irq() ; // Disable Interrupts
+    result = p_i2c->write(m_addr, (char *)data, len);
+    __enable_irq() ; // Enable Interrupts
+    return( result ) ;
+}
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