USCI I2C support.

[tinyos-2.x.git] / tos / chips / msp430 / usci / HplMsp430UsciInt0P.nc

diff --git a/tos/chips/msp430/usci/HplMsp430UsciInt0P.nc b/tos/chips/msp430/usci/HplMsp430UsciInt0P.nc
index 1ba7ef20668adcf4ec1fd65226b53db1a970fc53..d802a0bf3b66e2163998866bb63580d8934ff57f 100644 (file)
--- a/tos/chips/msp430/usci/HplMsp430UsciInt0P.nc
+++ b/tos/chips/msp430/usci/HplMsp430UsciInt0P.nc
@@ -26,13 +26,13 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
- 
+
 /**
  * HPL interrupt interface for the USCI0 peripheral.
- * 
+ *
  * @author R. Steve McKown <rsmckown@gmail.com>
  */
- 
+
 #include "Msp430Usci.h"
 #include "msp430hardware.h"
 
@@ -67,37 +67,54 @@ implementation
    * modes.
    */
   TOSH_SIGNAL(USCIAB0RX_VECTOR) {
-    if (READ_FLAG(UC0IFG, UCA0RXIFG)) {
+    if (READ_FLAG(UC0IFG & UC0IE, UCA0RXIE)) {
       volatile uint8_t c = UCA0RXBUF; /* read to clear UCA0RXIFG */
       if (READ_FLAG(UCA0CTL1, UCBRK)) {
-       UCA0CTL1 &= ~UCBRK;
+       CLR_FLAG(UCA0CTL1, UCBRK);
        if (READ_FLAG(UCA0CTL0, UCMODE_3) == UCMODE_3)
-         UCA0CTL1 &= ~UCDORM;
+         CLR_FLAG(UCA0CTL1, UCDORM);
        signal IntA.brk();
       } else
        signal IntA.rx(c);
-    } else if (READ_FLAG(UC0IFG, UCB0RXIFG))
+    } else if (READ_FLAG(UC0IFG & UC0IE, UCB0RXIE)) {
       signal IntB.rx(UCB0RXBUF); /* read clears UCB0RXIFG */
-    else if (READ_FLAG(UCB0STAT, UCALIFG))
+
+    /* FIXME: the arbitration of I2C interrupts are not vetted.  If, for example
+     * the UCALIFG bit gets set and neither it nor the corresponding interrupt
+     * enable bit is never unset, then an ISR configured for UCSTTIFG or
+     * UCSTPIFG will never be signalled.
+     */
+
+    } else if (READ_FLAG(UCB0STAT, UCALIFG)) {
+      CLR_FLAG(UCB0STAT, UCALIFG);
       signal IntB.i2cCal();
-    else if (READ_FLAG(UCB0STAT, UCNACKIFG))
-      signal IntB.i2cNak();
-    else if (READ_FLAG(UCB0STAT, UCSTTIFG))
+    } else if (READ_FLAG(UCB0STAT, UCNACKIFG)) {
+      CLR_FLAG(UCB0STAT, UCNACKIFG);
+      CLR_FLAG(UC0IFG, UCB0TXIFG); /* Errata USCI25; 'reset' means clear? */
+      signal IntB.i2cNack();
+    } else if (READ_FLAG(UCB0STAT, UCSTTIFG)) {
+      CLR_FLAG(UCB0STAT, UCSTTIFG);
       signal IntB.i2cStart();
-    else if (READ_FLAG(UCB0STAT, UCSTPIFG))
+    } else if (READ_FLAG(UCB0STAT, UCSTPIFG)) {
+      CLR_FLAG(UCB0STAT, UCSTPIFG);
       signal IntB.i2cStop();
+    }
   }
-  
+
   /* This interrupt vector signals transmit events.  USCI_A0 can receive events
    * for UART and SPI modes, while USCI_B0 can receive events for I2C and SPI
    * modes.
    */
   TOSH_SIGNAL(USCIAB0TX_VECTOR) {
-    if (READ_FLAG(UC0IFG, UCB0RXIFG))
-      signal IntB.rx(UCB0RXBUF); /* I2C receive */
-    else if (READ_FLAG(UC0IFG, UCA0TXIFG))
+    if (READ_FLAG(UC0IFG & UC0IE, UCB0RXIE)) {
+      /* I2C receive.  Do not read UCB0RXBUF here, as the code receiving
+       * IntB.rx() may first need to set stop and/or start bits.  The receiver
+       * must read UCB0RXBUF.
+       */
+      signal IntB.rx(0);
+    } else if (READ_FLAG(UC0IFG & UC0IE, UCA0TXIFG))
       signal IntA.tx();
-    else if (READ_FLAG(UC0IFG, UCB0TXIFG))
+    else if (READ_FLAG(UC0IFG & UC0IE, UCB0TXIFG))
       signal IntB.tx();
   }
 
@@ -106,7 +123,7 @@ implementation
   default async event void IntA.tx() {}
   /* i2c is not available for A devices, so the below are never signalled */
   default async event void IntA.i2cCal() {}
-  default async event void IntA.i2cNak() {}
+  default async event void IntA.i2cNack() {}
   default async event void IntA.i2cStart() {}
   default async event void IntA.i2cStop() {}
 
@@ -115,7 +132,7 @@ implementation
   default async event void IntB.rx(uint8_t byte) {}
   default async event void IntB.tx() {}
   default async event void IntB.i2cCal() {}
-  default async event void IntB.i2cNak() {}
+  default async event void IntB.i2cNack() {}
   default async event void IntB.i2cStart() {}
   default async event void IntB.i2cStop() {}
 }