forked from M-Labs/artiq
test_ad9910: relax SYNC window
Signed-off-by: Robert Jördens <rj@quartiq.de>
This commit is contained in:
parent
172633c7da
commit
6c00ab57c0
|
@ -414,7 +414,7 @@ class AD9910:
|
|||
self.cpld.io_update.pulse(1*us)
|
||||
|
||||
@kernel
|
||||
def tune_sync_delay(self, sync_delay_seed=8):
|
||||
def tune_sync_delay(self, sync_delay_seed=9):
|
||||
"""Find a stable SYNC_IN delay.
|
||||
|
||||
This method first locates the smallest SYNC_IN validity window at
|
||||
|
@ -430,8 +430,8 @@ class AD9910:
|
|||
"""
|
||||
dt = 14 # 1/(f_SYSCLK*75ps) taps per SYSCLK period
|
||||
max_delay = dt # 14*75ps > 1ns
|
||||
max_window = dt//4 + 1 # 2*75ps*4 = 600ps high > 1ns/2
|
||||
min_window = max(0, max_window - 2) # 2*75ps hold, 2*75ps setup
|
||||
max_window = dt//4 + 1 # 75ps*4 = 300ps setup and hold
|
||||
min_window = 1 # 1*75ps setup and hold
|
||||
for window in range(max_window - min_window + 1):
|
||||
window = max_window - window
|
||||
for in_delay in range(max_delay):
|
||||
|
@ -446,9 +446,8 @@ class AD9910:
|
|||
# integrate SMP_ERR statistics for a few hundred cycles
|
||||
# delay(10*us)
|
||||
err = urukul_sta_smp_err(self.cpld.sta_read())
|
||||
err = (err >> (self.chip_select - 4)) & 1
|
||||
delay(40*us) # slack
|
||||
if not err:
|
||||
if not (err >> (self.chip_select - 4)) & 1:
|
||||
window -= min_window # add margin
|
||||
self.set_sync(in_delay, window)
|
||||
self.clear_smp_err()
|
||||
|
|
Loading…
Reference in New Issue