urukul: add comment and doc about the AD9910 MASTER_RESET

This commit is contained in:
Robert Jördens 2018-03-20 17:40:03 +01:00
parent f17c0abfe4
commit 9ad1fd8f25
1 changed files with 4 additions and 1 deletions

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@ -166,9 +166,12 @@ class CPLD:
def init(self):
"""Initialize and detect Urukul.
Resets the DDS and verifies correct CPLD gateware version.
Resets the DDS I/O interface and verifies correct CPLD gateware
version.
Does not pulse the DDS MASTER_RESET as that confuses the AD9910.
"""
cfg = self.cfg_reg
# Don't pulse MASTER_RESET (m-labs/artiq#940)
self.cfg_reg = cfg | (0 << CFG_RST) | (1 << CFG_IO_RST)
proto_rev = urukul_sta_proto_rev(self.sta_read())
if proto_rev != STA_PROTO_REV_MATCH: