add error for reading before sending, and insert bit reads at the cor…

…rect locations
sajattack · May 14, 2019 · de66010 · de66010
1 parent e0c47d0
commit de66010
Showing 1 changed file with 19 additions and 9 deletions.
diff --git a/src/spi.rs b/src/spi.rs
@@ -5,7 +5,7 @@ use nb::block;
 
 #[derive(Debug)]
 pub enum Error {
-    Unimplemented,
+    NoData,
 }
 
 /// A Full-Duplex SPI implementation, takes 3 pins, and a timer running at 2x
@@ -22,7 +22,7 @@ where
     mosi: Mosi,
     sck: Sck,
     timer: Timer,
-    read_val: u8, 
+    read_val: Option<u8>, 
 }
 
 impl <Miso, Mosi, Sck, Timer> SPI<Miso, Mosi, Sck, Timer>
@@ -45,7 +45,15 @@ where
             mosi: mosi,
             sck: sck,
             timer: timer,
-            read_val: 0,
+            read_val: None,
+        }
+    }
+
+    fn read_bit(&mut self) {
+        if self.miso.is_high() {
+            self.read_val = Some((self.read_val.unwrap_or(0) << 1) | 1);
+        } else {
+            self.read_val = Some(self.read_val.unwrap_or(0) << 1);
         }
     }
 }
@@ -60,7 +68,10 @@ where
     type Error = Error;
 
     fn read(&mut self) -> nb::Result<u8, Error> {
-        Ok(self.read_val)
+        match self.read_val {
+            Some(val) => Ok(val),
+            None => Err(nb::Error::Other(Error::NoData))
+        }
     }
 
     fn send(&mut self, byte: u8) -> nb::Result<(), Self::Error> {
@@ -72,32 +83,31 @@ where
             } else {
                 self.mosi.set_low();
             }
-            if self.miso.is_high() {
-                self.read_val = (self.read_val << 1) | 1
-            } else {
-                self.read_val = self.read_val << 1
-            }
             if self.mode.phase == CaptureOnFirstTransition {
                 if self.mode.polarity == IdleLow {
                     block!(self.timer.wait()).ok(); 
                     self.sck.set_high();
+                    self.read_bit();
                     block!(self.timer.wait()).ok(); 
                     self.sck.set_low();
                 } else {
                     block!(self.timer.wait()).ok(); 
                     self.sck.set_low();
+                    self.read_bit();
                     block!(self.timer.wait()).ok(); 
                     self.sck.set_high();
                 }
             } else {
                 if self.mode.polarity == IdleLow {
                     self.sck.set_high();
                     block!(self.timer.wait()).ok(); 
+                    self.read_bit();
                     self.sck.set_low();
                     block!(self.timer.wait()).ok(); 
                 } else {
                     self.sck.set_low();
                     block!(self.timer.wait()).ok(); 
+                    self.read_bit();
                     self.sck.set_high();
                     block!(self.timer.wait()).ok(); 
                 }