add both channels in loopback

fast-servo/pyfastservo/adc.py

@@ -152,6 +152,8 @@ def configure_ltc2195():
         main_adc_test_mode(spi, False)
         verify_adc_registers(spi, {0x02: 0x11})  # Verify test mode is off
         
+        print_adc_channels()
+
         enable_adc_afe()
 
     finally:

fast-servo/pyfastservo/dac.py

@@ -127,13 +127,13 @@ def configure_ad9117():
         configure_dac(spi)
         dac_self_calibration(spi)
 
+        # Enable DAC outputs
+        spi_write(spi, 0x01, spi_read(spi, 0x01) & ~((1 << 4) | (1 << 3)))
+
         power_down(0, False)
         power_down(1, False)
         manual_override(True)
 
-        # Enable DAC outputs
-        spi_write(spi, 0x01, spi_read(spi, 0x01) & ~((1 << 4) | (1 << 3)))
-
         print("AD9117 configuration completed successfully")
         return True
 

fast-servo/pyfastservo/loopback.py

@@ -0,0 +1,60 @@
+import time
+from pyfastservo import adc, dac
+from pyfastservo.common import (
+    ADC_CH0_HIGH_ADDR, ADC_CH0_LOW_ADDR,
+    ADC_CH1_HIGH_ADDR, ADC_CH1_LOW_ADDR,
+    CH0_HIGH_WORD_ADDR, CH0_LOW_WORD_ADDR,
+    CH1_HIGH_WORD_ADDR, CH1_LOW_WORD_ADDR,
+    read_from_memory, write_to_memory
+)
+
+def read_adc(channel):
+    if channel == 0:
+        return adc.read_adc_channel(ADC_CH0_HIGH_ADDR, ADC_CH0_LOW_ADDR)
+    elif channel == 1:
+        return adc.read_adc_channel(ADC_CH1_HIGH_ADDR, ADC_CH1_LOW_ADDR)
+    else:
+        raise ValueError("Invalid ADC channel")
+
+def write_dac(channel, value):
+    dac.set_dac_output(value, channel)
+
+def read_dac(channel):
+    if channel == 0:
+        high_word = read_from_memory(CH0_HIGH_WORD_ADDR, 1)[0]
+        low_word = read_from_memory(CH0_LOW_WORD_ADDR, 1)[0]
+    elif channel == 1:
+        high_word = read_from_memory(CH1_HIGH_WORD_ADDR, 1)[0]
+        low_word = read_from_memory(CH1_LOW_WORD_ADDR, 1)[0]
+    else:
+        raise ValueError("Invalid DAC channel")
+    return (high_word << 8) | low_word
+
+def perform_loopback_test(channel, test_value):
+    print(f"\nTesting Channel {channel}")
+    print(f"Setting DAC CH{channel} output to {test_value}...")
+    write_dac(channel, test_value)
+    time.sleep(0.1)  # Allow time for the signal to stabilize
+
+    print(f"Reading ADC CH{channel} value...")
+    adc_value = read_adc(channel)
+    print(f"ADC CH{channel} readback: {adc_value}")
+
+    print(f"Reading DAC CH{channel} value...")
+    dac_value = read_dac(channel)
+    print(f"DAC CH{channel} readback: {dac_value}")
+
+    if abs(test_value - adc_value) <= 2 and abs(test_value - dac_value) <= 2:
+        print(f"Loopback test for Channel {channel} PASSED!")
+    else:
+        print(f"Loopback test for Channel {channel} FAILED!")
+        print(f"Expected: {test_value}, ADC: {adc_value}, DAC: {dac_value}")
+
+def main():
+    test_value = 0x0FFF  # Mid-range value (4095 in decimal)
+    
+    perform_loopback_test(0, test_value)
+    perform_loopback_test(1, test_value)
+
+if __name__ == "__main__":
+    main()

flake.lock

@@ -18,11 +18,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1719838683,
+        "lastModified": 1723938990,
-        "narHash": "sha256-Zw9rQjHz1ilNIimEXFeVa1ERNRBF8DoXDhLAZq5B4pE=",
+        "narHash": "sha256-9tUadhnZQbWIiYVXH8ncfGXGvkNq3Hag4RCBEMUk7MI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "d032c1a6dfad4eedec7e35e91986becc699d7d69",
+        "rev": "c42fcfbdfeae23e68fc520f9182dde9f38ad1890",
         "type": "github"
       },
       "original": {
@@ -64,11 +64,11 @@
     "src-migen": {
       "flake": false,
       "locked": {
-        "lastModified": 1715484909,
+        "lastModified": 1721561053,
-        "narHash": "sha256-4DCHBUBfc/VA+7NW2Hr0+JP4NnKPru2uVJyZjCCk0Ws=",
+        "narHash": "sha256-z3LRhNmKZrjr6rFD0yxtccSa/SWvFIYmb+G/D5d2Jd8=",
         "owner": "m-labs",
         "repo": "migen",
-        "rev": "4790bb577681a8c3a8d226bc196a4e5deb39e4df",
+        "rev": "9279e8623f8433bc4f23ac51e5e2331bfe544417",
         "type": "github"
       },
       "original": {

flake.nix

@@ -481,7 +481,7 @@
         inherit migen misoc vivado;
       };
       packages.armv7l-linux = {
-        inherit fast-servo-gateware linien-server;
+        inherit fast-servo-gateware linien-server pyfastservo;
       } //
       (board-package-set { board = "zc706"; }) //
       (board-package-set { board = "fast-servo"; });

not-os-patches/pr-28.patch

@@ -1,5 +1,5 @@
 diff --git a/base.nix b/base.nix
-index 7eaee32..3ade454 100644
+index 7eaee32..9aa338e 100644
 --- a/base.nix
 +++ b/base.nix
 @@ -27,6 +27,11 @@ with lib;
@@ -14,7 +14,7 @@ index 7eaee32..3ade454 100644
      not-os.simpleStaticIp = mkOption {
        type = types.bool;
        default = false;
-@@ -84,17 +89,27 @@ with lib;
+@@ -84,17 +89,25 @@ with lib;
      };
      environment.etc = {
        "nix/nix.conf".source = pkgs.runCommand "nix.conf" {} ''
@@ -31,8 +31,6 @@ index 7eaee32..3ade454 100644
 +        extra-sandbox-paths = /bin/sh=${pkgs.runtimeShell} $(echo $extraPaths)
 +        max-jobs = auto
 +        sandbox = true
-+        substituters = https://cache.armv7l.xyz
-+        trusted-public-keys = cache.armv7l.xyz-1:kBY/eGnBAYiqYfg0fy0inWhshUo+pGFM3Pj7kIkmlBk=
 +        trusted-users = root
          EOF
        '';