# HG changeset patch
# Parent 4fa55f1cd74ede8ca83e5c099bec2dcf442e7042
Control the si570 frequency directly via registers

diff -r 4fa55f1cd74e quisk_conf_defaults.py
--- a/quisk_conf_defaults.py	Wed Feb 16 17:11:15 2011 -0500
+++ b/quisk_conf_defaults.py	Wed Feb 16 17:14:54 2011 -0500
@@ -196,6 +196,15 @@
 # name_of_sound_play = "hw:0"		# Play back on this soundcard
 # playback_rate = 48000				# Radio sound play rate, default 48000
 
+# If you are using a DG8SAQ interface to set a Si570 clock directly, set
+# this to True.  Complex controllers which have their own internal
+# crystal calibration do not require this.
+si570_direct_control = False
+# This is the Si570 startup frequency in Hz.  114.285MHz is the typical
+# value from the data sheet; you can use 'usbsoftrock calibrate' to find
+# the value for your device.
+si570_xtal_freq = 114285000
+
 # This is the received radio sound playback rate.  The default will
 # be 48 kHz for the SDR-IQ and UDP port samples, and sample_rate for sound
 # card capture.  Set it yourself for other rates or hardware.
diff -r 4fa55f1cd74e softrock/hardware_usb.py
--- a/softrock/hardware_usb.py	Wed Feb 16 17:11:15 2011 -0500
+++ b/softrock/hardware_usb.py	Wed Feb 16 17:14:54 2011 -0500
@@ -1,7 +1,7 @@
 # Please do not change this hardware control module for Quisk.
 # It provides USB control of SoftRock hardware.
 
-import struct, threading, time, traceback
+import struct, threading, time, traceback, math
 from quisk_hardware_model import Hardware as BaseHardware
 import _quisk as QS
 
@@ -16,6 +16,16 @@
 # I2C-address of the SI570;  Thanks to Joachim Schneider, DB6QS
 si570_i2c_address = 0x55
 
+# Thanks to Ethan Blanton, KB8OJH, for this patch for the Si570 (many SoftRocks):
+# These are used by SetFreqByDirect(); see below.
+# The Si570 DCO must be clamped between these values
+SI570_MIN_DCO = 4.85e9
+SI570_MAX_DCO = 5.67e9
+# The Si570 has 6 valid HSDIV values.  Subtract 4 from HSDIV before
+# stuffing it.  We want to find the highest HSDIV first, so start
+# from 11.
+SI570_HSDIV_VALUES = [11, 9, 7, 6, 5, 4]
+
 IN =  usb.util.build_request_type(usb.util.CTRL_IN,  usb.util.CTRL_TYPE_VENDOR, usb.util.CTRL_RECIPIENT_DEVICE)
 OUT = usb.util.build_request_type(usb.util.CTRL_OUT, usb.util.CTRL_TYPE_VENDOR, usb.util.CTRL_RECIPIENT_DEVICE)
 
@@ -69,8 +79,11 @@
       self.key_thread = None
   def ChangeFrequency(self, tune, vfo, source='', band='', event=None):
     if self.usb_dev and self.vfo != vfo:
-      if self.SetFreqByValue(vfo):
-        self.vfo = vfo
+      if self.conf.si570_direct_control:
+        if self.SetFreqByDirect(vfo):
+          self.vfo = vfo
+      elif self.SetFreqByValue(vfo):
+         self.vfo = vfo
       if DEBUG:
         print 'Change to', vfo
         print 'Run freq', self.GetFreq()
@@ -123,6 +136,52 @@
       if DEBUG: traceback.print_exc()
     else:
       return True
+  def SetFreqByDirect(self, freq):	# Thanks to Ethan Blanton, KB8OJH
+    # For now, find the minimum DCO speed that will give us the
+    # desired frequency; if we're slewing in the future, we want this
+    # to additionally yield an RFREQ ~= 512.
+    freq = int(freq * 4)
+    if freq == 0:
+      return False
+    dco_new = None
+    hsdiv_new = 0
+    n1_new = 0
+    for hsdiv in SI570_HSDIV_VALUES:
+      n1 = int(math.ceil(SI570_MIN_DCO / (freq * hsdiv)))
+      if n1 < 1:
+        n1 = 1
+      else:
+        n1 = ((n1 + 1) / 2) * 2
+      dco = (freq * 1.0) * hsdiv * n1
+      # Since we're starting with max hsdiv, this can only happen if
+      # freq was larger than we can handle
+      if n1 > 128:
+        continue
+      if dco < SI570_MIN_DCO or dco > SI570_MAX_DCO:
+        # This really shouldn't happen
+        continue
+      if not dco_new or dco < dco_new:
+        dco_new = dco
+        hsdiv_new = hsdiv
+        n1_new = n1
+    if not dco_new:
+      # For some reason, we were unable to calculate a frequency.
+      # Probably because the frequency requested is outside the range
+      # of our device.
+      return False		# Failure
+    rfreq = dco_new / self.conf.si570_xtal_freq
+    rfreq_int = int(rfreq)
+    rfreq_frac = int(round((rfreq - rfreq_int) * 2**28))
+    # It looks like the DG8SAQ protocol just passes r7-r12 straight
+    # To the Si570 when given command 0x30.  Easy enough.
+    # n1 is stuffed as n1 - 1, hsdiv is stuffed as hsdiv - 4.
+    hsdiv_new = hsdiv_new - 4
+    n1_new = n1_new - 1
+    s = struct.Struct('>BBL').pack((hsdiv_new << 5) + (n1_new >> 2),
+                                   ((n1_new & 0x3) << 6) + (rfreq_int >> 4),
+                                   ((rfreq_int & 0xf) << 28) + rfreq_frac)
+    self.usb_dev.ctrl_transfer(OUT, 0x30, si570_i2c_address + 0x700, 0, s)
+    return True		# Success
 
 class KeyThread(threading.Thread):
   """Create a thread to monitor the key state."""