What a wonderful 3d!!!!
Thankyou for this terrific sectionNow this is a transponder.
Garmin GPSmap 196 handheld GPS:
The main board:
Samsung s3c44 66MHz processor – one of the original ARM designs from around 25 years ago. Plus some FLASH and RAM.
The GPS module, with a Garmin custom chip
This is quite funny. Reminds me of the famous “Bill sux” one which was apparently fake.
It’s amazing how many chips where needed back then. Today you could do the whole thing and much more with this module (antenna bottom left) which can track about 30 satellites at 25Hz, WAAS/EGNOS, and costs about €20 (1-off).
I still treasure my Garmin 196, and they tend to feature on the hard core Super Cub Alaska videos. Still supported, great design.
Interesting it uses ARM. The GPSMAP 195 used an 80386 (and probably why it ate batteries so quickly).
It is one of the old ARMs which ran both full and thumb opcodes, seemingly.
It is a lot of power for this sort of product. I reckon that – with a GPS coprocessor – you could do it with a Z80 at 4MHz 
although painfully due to the limited address space. They also do need low power modes.
The KLN94 uses a 386 and a HC16 – here and this all dates back to when Garmin started, with a load of ex King engineers. The 186 was very popular back then for embedded. But yes all these draw a lot of power.
Compare the above with this which I am coding now. It is running this
at the same time as running a web server, USB VCP, ethernet, DHCP, NTP (client and server), GPS NMEA (WAAS/EGNOS) to ARINC429… and ir draws about 300mA.
I chucked away the 196 because it was shutting down after about 10 mins, but the batteries were ok. I bought it on Ebay for about £10, years ago, and it lived in my emergency bag. I put in new batteries every year but the last lot leaked badly (Duracells are overpriced crap). If I am sitting in the liferaft and trying to call up an airliner on 121.50, I should have my phone for the GPS coordinates
Peter wrote:
If I am sitting in the liferaft and trying to call up an airliner on 121.50, I should have my phone for the GPS coordinates
Especially given quite a few newer phones (e.g. iPhone) are water resistant. Mine’s been in the Irish Sea a few times and is no worse for wear. (Also, if there’s one thing I’ve learned from Saving Lives at Sea, always carry a PLB, too).
That’s a really good site. He’s a GA pilot living in Singapore, and commented on that some of these avionics are made there! In fact I could never understand why anybody in the US would make high value stuff in Singapore (or China, etc) but this is common for King stuff. I downloaded the MMs for my private collection
The volumes back then must have been reasonable because one of them uses a ROM microprocessor, and you had to buy at least 10k to get those. OTOH one needed to buy up a lot of strategic stock, because your product would run for much longer than the chips. So you had to be confident of your code, but that wasn’t so hard because the micros in these things really just did the user interface. “Digital” boxes appeared in autopilots with the KFC225 (which AFAICT runs the algorithms using signed integer maths) in late 1990s, but radios never went digital (DDS, SDR, etc).
A pity Narco stuff had poor reliability. Their MMs are nicely written. This bit is curious:
This bit is curious:
Maybe it has something to do with DME/DME updating, which is mainly used by airliners. More accurate than gps and ins. For this reason, even as VORs are decommissioned, the DMEs remain in place.
