One wire slave: fix presence timing, disable irq early (#348)

lib/onewire/one_wire_slave.cpp

@@ -256,24 +256,23 @@ bool OneWireSlave::bus_start(void) {
     if(device == nullptr) {
         result = false;
     } else {
+        __disable_irq();
         pin_init_opendrain_in_isr_ctx();
         error = OneWireSlaveError::NO_ERROR;
 
         if(show_presence()) {
-            __disable_irq();
-
             // TODO think about multiple command cycles
             receive_and_process_cmd();
             result =
                 (error == OneWireSlaveError::NO_ERROR ||
                  error == OneWireSlaveError::INCORRECT_ONEWIRE_CMD);
 
-            __enable_irq();
         } else {
             result = false;
         }
 
         pin_init_interrupt_in_isr_ctx();
+        __enable_irq();
     }
 
     return result;

lib/onewire/one_wire_timings.h

@@ -41,7 +41,7 @@ public:
     constexpr static const OneWiteTimeType RESET_MAX = 960;
 
     constexpr static const OneWiteTimeType PRESENCE_TIMEOUT = 20;
-    constexpr static const OneWiteTimeType PRESENCE_MIN = 160;
+    constexpr static const OneWiteTimeType PRESENCE_MIN = 100;
     constexpr static const OneWiteTimeType PRESENCE_MAX = 480;
 
     constexpr static const OneWiteTimeType MSG_HIGH_TIMEOUT = 15000;