ad5360: port to spi2

* kc705 nist_clock target gateware
* coredevice driver
* moninj code
* test/example/device_db

This is untested as we don't have a AD5360 board right now.
Will be tested with Zotino v1.1

m-labs/artiq#926

artiq/coredevice/ad5360.py

@@ -6,14 +6,16 @@ time is an error.
 """
 
 
-from artiq.language.core import (kernel, portable, delay_mu, delay)
+from artiq.language.core import (kernel, portable, delay_mu, delay, now_mu,
+                                 at_mu)
 from artiq.language.units import ns, us
-from artiq.coredevice import spi
+from artiq.coredevice import spi2 as spi
 
 # Designed from the data sheets and somewhat after the linux kernel
 # iio driver.
 
-_AD5360_SPI_CONFIG = (0*spi.SPI_OFFLINE | 0*spi.SPI_CS_POLARITY |
+_AD5360_SPI_CONFIG = (0*spi.SPI_OFFLINE | 1*spi.SPI_END |
+                      0*spi.SPI_INPUT | 0*spi.SPI_CS_POLARITY |
                       0*spi.SPI_CLK_POLARITY | 1*spi.SPI_CLK_PHASE |
                       0*spi.SPI_LSB_FIRST | 0*spi.SPI_HALF_DUPLEX)
 
@@ -27,6 +29,7 @@ _AD5360_CMD_SPECIAL = 0 << 22
 def _AD5360_WRITE_CHANNEL(c):
     return (c + 8) << 16
 
+
 _AD5360_SPECIAL_NOP = 0 << 16
 _AD5360_SPECIAL_CONTROL = 1 << 16
 _AD5360_SPECIAL_OFS0 = 2 << 16
@@ -38,6 +41,7 @@ _AD5360_SPECIAL_READ = 5 << 16
 def _AD5360_READ_CHANNEL(ch):
     return (ch + 8) << 7
 
+
 _AD5360_READ_X1A = 0x000 << 7
 _AD5360_READ_X1B = 0x040 << 7
 _AD5360_READ_OFFSET = 0x080 << 7
@@ -57,31 +61,34 @@ class AD5360:
       (optional). Needs to be explicitly initialized to high.
     :param chip_select: Value to drive on the chip select lines
       during transactions.
+    :param div_write: SPI clock divider during writes
+    :param div_read: SPI clock divider during reads
     """
+    kernel_invariants = {"bus", "core", "chip_select", "div_read", "div_write"}
 
-    def __init__(self, dmgr, spi_device, ldac_device=None, chip_select=1):
+    def __init__(self, dmgr, spi_device, ldac_device=None, chip_select=1,
+                 div_write=4, div_read=7):
         self.core = dmgr.get("core")
         self.bus = dmgr.get(spi_device)
         if ldac_device is not None:
             self.ldac = dmgr.get(ldac_device)
         self.chip_select = chip_select
+        # write: 2*8ns >= 10ns = t_6 (clk falling to cs_n rising)
+        # 4*8ns >= 20ns = t_1 (clk cycle time)
+        self.div_write = div_write
+        # read: 4*8*ns >= 25ns = t_22 (clk falling to miso valid)
+        self.div_read = div_read
 
     @kernel
-    def setup_bus(self, write_div=4, read_div=7):
+    def setup_bus(self):
         """Configure the SPI bus and the SPI transaction parameters
         for this device. This method has to be called before any other method
         if the bus has been used to access a different device in the meantime.
 
-        This method advances the timeline by the duration of two
+        This method advances the timeline by one coarse RTIO cycle.
-        RTIO-to-Wishbone bus transactions.
-
-        :param write_div: Write clock divider.
-        :param read_div: Read clock divider.
         """
-        # write: 2*8ns >= 10ns = t_6 (clk falling to cs_n rising)
+        self.bus.set_config_mu(_AD5360_SPI_CONFIG, 24, self.div_write,
-        # read: 4*8*ns >= 25ns = t_22 (clk falling to miso valid)
+                               self.chip_select)
-        self.bus.set_config_mu(_AD5360_SPI_CONFIG, write_div, read_div)
-        self.bus.set_xfer(self.chip_select, 24, 0)
 
     @kernel
     def write(self, data):
@@ -126,8 +133,8 @@ class AD5360:
     def read_channel_sync(self, channel=0, op=_AD5360_READ_X1A):
         """Read a channel register.
 
-        This method advances the timeline by the duration of :meth:`write` plus
+        This method advances the timeline by the duration of two :meth:`write`
-        three RTIO-to-Wishbone transactions.
+        plus two coarse RTIO cycles.
 
         :param channel: Channel number to read from.
         :param op: Operation to perform, one of :const:`_AD5360_READ_X1A`,
@@ -138,11 +145,13 @@ class AD5360:
         channel &= 0x3f
         self.write(_AD5360_CMD_SPECIAL | _AD5360_SPECIAL_READ | op |
                    _AD5360_READ_CHANNEL(channel))
-        self.bus.set_xfer(self.chip_select, 0, 24)
+        self.bus.set_config_mu(_AD5360_SPI_CONFIG | spi.SPI_INPUT, 24,
+                               self.div_read, self.chip_select)
+        delay(270*ns)  # t_21 min sync high in readback
         self.write(_AD5360_CMD_SPECIAL | _AD5360_SPECIAL_NOP)
-        self.bus.read_async()
+        self.bus.set_config_mu(_AD5360_SPI_CONFIG, 24,
-        self.bus.set_xfer(self.chip_select, 24, 0)
+                               self.div_write, self.chip_select)
-        return self.bus.input_async() & 0xffff
+        return self.bus.read() & 0xffff
 
     @kernel
     def load(self):
@@ -168,15 +177,13 @@ class AD5360:
           :const:`_AD5360_CMD_OFFSET`, :const:`_AD5360_CMD_GAIN`
           (default: :const:`_AD5360_CMD_DATA`).
         """
+        t0 = now_mu()
+        # t10 max busy low for one channel
+        t_10 = self.core.seconds_to_mu(1.5*us)
         # compensate all delays that will be applied
-        delay_mu(-len(values)*(self.bus.xfer_period_mu +
+        delay_mu(-len(values)*self.bus.xfer_period_mu-t_10)
-                               self.bus.write_period_mu +
-                               self.bus.ref_period_mu) -
-                 3*self.bus.ref_period_mu -
-                 self.core.seconds_to_mu(1.5*us))
         for i in range(len(values)):
             self.write_channel(i, values[i], op)
-        delay_mu(3*self.bus.ref_period_mu +  # latency alignment ttl to spi
+        delay_mu(t_10)
-                 self.core.seconds_to_mu(1.5*us))  # t10 max busy low for one channel
         self.load()
-        delay_mu(-2*self.bus.ref_period_mu)  # load(), t13
+        at_mu(t0)

artiq/examples/kc705_nist_clock/device_db.py

@@ -173,7 +173,7 @@ device_db = {
     },
     "spi_zotino": {
         "type": "local",
-        "module": "artiq.coredevice.spi",
+        "module": "artiq.coredevice.spi2",
         "class": "SPIMaster",
         "arguments": {"channel": 30}
     },
@@ -187,7 +187,12 @@ device_db = {
         "type": "local",
         "module": "artiq.coredevice.ad5360",
         "class": "AD5360",
-        "arguments": {"spi_device": "spi_zotino", "ldac_device": "ttl_zotino_ldac"}
+        "arguments": {
+            "spi_device": "spi_zotino",
+            "ldac_device": "ttl_zotino_ldac",
+            "div_write": 30,
+            "div_read": 40
+        }
     },
 
     "spi_urukul": {

artiq/examples/kc705_nist_clock/repository/ad5360.py

@@ -13,7 +13,7 @@ class AD5360Test(EnvExperiment):
         self.core.reset()
         delay(5*ms)  # build slack for shift register set
         self.fmcdio_dirctl.set(self, 0x00008800)
-        self.dac.setup_bus(write_div=30, read_div=40)
+        self.dac.setup_bus()
         self.dac.write_offsets()
         self.led.on()
         delay(400*us)

artiq/gateware/rtio/phy/ad5360_monitor.py

@@ -1,6 +1,6 @@
 from migen import *
 
-from artiq.coredevice.spi import SPI_XFER_ADDR, SPI_DATA_ADDR
+from artiq.coredevice.spi2 import SPI_CONFIG_ADDR, SPI_DATA_ADDR
 from artiq.coredevice.ad5360 import _AD5360_CMD_DATA, _AD5360_WRITE_CHANNEL
 
 
@@ -22,20 +22,20 @@ class AD5360Monitor(Module):
                 If(ldac_oif.stb & ttl_level_adr & ~ldac_oif.data[0],
                     [probe.eq(write_target) for probe, write_target in zip(self.probes, write_targets)]
                 )
-        
+
         spi_oif = spi_rtlink.o
 
         selected = Signal()
         if cs_onehot:
             self.sync.rio_phy += [
-                If(spi_oif.stb & (spi_oif.address == SPI_XFER_ADDR),
+                If(spi_oif.stb & (spi_oif.address == SPI_CONFIG_ADDR),
-                    selected.eq(spi_oif.data[cs_no])
+                    selected.eq(spi_oif.data[24 + cs_no])
                 )
             ]
         else:
             self.sync.rio_phy += [
-                If(spi_oif.stb & (spi_oif.address == SPI_XFER_ADDR),
+                If(spi_oif.stb & (spi_oif.address == SPI_CONFIG_ADDR),
-                    selected.eq(spi_oif.data[:16] == cs_no)
+                    selected.eq(spi_oif.data[24:] == cs_no)
                 )
             ]
 

artiq/gateware/targets/kc705.py

@@ -341,8 +341,8 @@ class NIST_CLOCK(_StandaloneBase):
             self.submodules += phy
             rtio_channels.append(rtio.Channel.from_phy(phy))
 
-        sdac_phy = spi.SPIMaster(self.platform.request("zotino_spi_p"),
+        sdac_phy = spi2.SPIMaster(self.platform.request("zotino_spi_p"),
-                                 self.platform.request("zotino_spi_n"))
+                                  self.platform.request("zotino_spi_n"))
         self.submodules += sdac_phy
         rtio_channels.append(rtio.Channel.from_phy(sdac_phy, ififo_depth=4))