Small Transport; Low Wing; 2 Recip Eng
Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 47; Flight Crew Total 1810; Flight Crew Type 1230
Situational Awareness; Confusion; Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Aircraft; Equipment / Tooling; Human Factors
ATC advised I was off course from the route given in the IFR clearance. After advising off course; ECHOE Intersection/V-70 was given for the course correction because I had passed PSX and was heading to EFD instead of DELVE intersection. During the time of the deviation; I was checking ATIS and loading the procedure to 17R into EFD. Also; I was using the moving map on my Garmin GMX 200 display. Apparently either the Garmin GNS 530W or the Garmin GMX 200 system froze and stopped the moving map. Not sure which unit stopped working; thus causing me to fly thru the PSX fix while setting up for the approach into EFD.  Garmin suggested reloading all my navigation cards.  Jeppesen allowed me to reload the data to both my navigation cards.During the time I was in contact with ATC; I originally gave them the incorrect information on our route because I misunderstood his question about the route. After the second query from ATC; I was able to give him the information and the problem was corrected. I did not query the controller afterwards because he seemed very busy.
GA pilot reported a malfunction of either the Garmin GMX 200 or Garmin GNS 530W in which the moving map froze resulting in navigating off course.