diff --git a/fast-servo/pyfastservo/adc.py b/fast-servo/pyfastservo/adc.py
index 69fefcf..e04a47e 100644
--- a/fast-servo/pyfastservo/adc.py
+++ b/fast-servo/pyfastservo/adc.py
@@ -54,7 +54,7 @@ def main_adc_config(test_pattern):
         spi.open(MAIN_ADC_BUS, MAIN_ADC_DEVICE)
         spi.max_speed_hz = 50000
         spi.mode = 0b00  # CPOL = 0 CPHA = 0
-        spi.cshigh = True
+        spi.cshigh = False
         # spi.read0 = False
 
         spi_buffer = [0x00, 0x80]  # reset
@@ -121,7 +121,7 @@ def main_adc_test_mode(enable):
         spi.open(MAIN_ADC_BUS, MAIN_ADC_DEVICE)
         spi.max_speed_hz = 50000
         spi.mode = 0b00  # CPOL = 0 CPHA = 0
-        spi.cshigh = True
+        spi.cshigh = False
         # spi.read0 = True
 
         reg_contents = (
@@ -292,7 +292,7 @@ def adc_aux_read(port, type, pin):
         spi.open(1, 3)  # AUX ADC 1?
         spi.max_speed_hz = 5000
         spi.mode = 0b00
-        spi.cshigh = True
+        spi.cshigh = False
 
         read_buffer = spi.xfer2(write_buffer)
         mu_voltage = read_buffer[0] << 8 | read_buffer[1] >> 2
diff --git a/fast-servo/pyfastservo/dac.py b/fast-servo/pyfastservo/dac.py
index e16a14a..a523ffc 100644
--- a/fast-servo/pyfastservo/dac.py
+++ b/fast-servo/pyfastservo/dac.py
@@ -45,7 +45,7 @@ def main_dac_init():
         spi.open(MAIN_DAC_BUS, MAIN_DAC_DEVICE)
         spi.max_speed_hz = 5000
         spi.mode = 0b00  # CPOL = 0 CPHA = 0
-        spi.cshigh = True
+        spi.cshigh = False
 
         spi_buffer = [0x00, 0x10]  # software reset
         spi.xfer2(spi_buffer)