Simrad ST90 - Synchronization Sequences

442703/B
201
ALocalconnection
BConnectiononremotedevice
CFemale9-pinD-Subminiatureconnector
DMale9-pinD-Subminiatureconnector
Note
RS-422communicationportscannotbeusedfor
synchronizationpurposes.Theportyouwishtousemust
besettoRS-232.
Relatedtopics
Cabledrawingsandspecications,page206
SettinguptheST90inasynchronizedsystem,page199
Synchronizationsequences
Inmanyapplications,thesynchronisationinterfaceisbasedonanRS-232serialport.
WhenyouconnecttwosystemsforsynchronisationusingCleartoSend(CTS)and
RequesttoSend(RTS),onesystemmustsetupasa"Master"andtheotherasa"Slave".
WhentheST90is"Master"inasystem,thesynchronizationcaneithertakeplaceinFree
runningmode,orinWaitforslavemode.
Slavemode
WhentheST90issetupinSlavemode,itmustreceiveatriggersignalfromaperipheral
systemeverytimetheST90isgoingtotransmit.Thistriggersignalisconnectedtoa
serialportontheProcessorUnit,andtheClearToSend(CTS)pinisusedtogivethe
ST90an"event"message.ThemessageisprocessedbytheST90software,anditwill(if
thepreviouspinghasbeennished)startthepingsequence.
Asanacknowledgementtothesynchronizationtrigger,theST90setstheReadyToSend
(RTS)signaltoalogic"low"beforetransmitting.ThisindicatesthattheST90is"busy".
Oncethetransmissionandreceptionsequenceends,theST90setstheReadyToSend
(RTS)signaltoalogic"high"toindicatethatitisreadyforthenextping.
Mastermode
WhentheST90is"Master"inasystem,thesynchronizationcaneithertakeplaceinFree
runningmode,orinWaitforslavemode.
Cablelayoutandinterconnections