Added interpose driver from DLS

Added a low-level interpose driver to allow usage of stream devices.

src/turboPmacController.h

@@ -103,15 +103,30 @@ class turboPmacController : public sinqController {
                                      int axisNo_, const char *functionName,
                                      int lineNumber);
 
+    /**
+     * @brief Perform a hardware flush (clearing of communication buffers)
+     *
+     * The PMAC controllers hardware buffers can be flushed (see Turbo PMAC user
+     * manual, p. 414). This "freezes" the PMAC for around 10 ms and should
+     * therefore only be done if it is necessary (i.e. not as part of the
+     * regular communication procedure).
+     *
+     * @return asynStatus
+     */
+    asynStatus doFlushHardware();
+
     // Accessors for additional PVs
     int rereadEncoderPosition() { return rereadEncoderPosition_; }
     int readConfig() { return readConfig_; }
+    int flushHardware() { return flushHardware_; }
 
     // Set the maximum buffer size. This is an empirical value which must be
     // large enough to avoid overflows for all commands to the device /
     // responses from it.
     static const uint32_t MAXBUF_ = 200;
 
+    asynUser *pasynInt32SyncIOipPort() { return pasynInt32SyncIOipPort_; }
+
   protected:
     /*
     Timeout for the communication process in seconds
@@ -120,11 +135,15 @@ class turboPmacController : public sinqController {
 
     char lastResponse[MAXBUF_];
 
+    // User for writing int32 values to the port driver.
+    asynUser *pasynInt32SyncIOipPort_;
+
     // Indices of additional PVs
 #define FIRST_turboPmac_PARAM rereadEncoderPosition_
     int rereadEncoderPosition_;
     int readConfig_;
-#define LAST_turboPmac_PARAM readConfig_
+    int flushHardware_;
+#define LAST_turboPmac_PARAM flushHardware_
 };
 #define NUM_turboPmac_DRIVER_PARAMS                                            \
     (&LAST_turboPmac_PARAM - &FIRST_turboPmac_PARAM + 1)