Search found 702 matches

by Daniel Wee
Wed 11 Mar 11 2009 5:37 pm
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Okay, I think the drawing primitives are now all done. I do need to think about how and when to set the warning conditions - ie. low voltage warnings, range warnings, and so on. Under ideal conditions the screen draw can be as low as 13.6ms or a 73.5Hz rate. This is without the rendering of the arti...
by Daniel Wee
Wed 11 Mar 11 2009 11:16 am
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Okay, buffer size is now up to 1024-bytes in order to accommodate for future 10Hz GPS data streams. Buffer no longer overflows. SPI Rendering issues have been largely resolved - no more lockups. There is the very rare data corruption and it is uncertain what the cause of this is. We also fixed some ...
by Daniel Wee
Wed 11 Mar 11 2009 9:22 am
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

We current have a 256-byte serial buffer running in circular mode. At 115200 baud, each character takes 10/115200s or 86.8us. This means that the buffer will fill up in 22.2ms. Given that a full NMEA frame of RMC, GGA and GSV messages take about 1104-bytes (95.8ms to send) or so, we have more than e...
by Daniel Wee
Wed 11 Mar 11 2009 2:51 am
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Need to correct the Voltage1 display. Apparently we're reading the voltage through a protection diode (that I didn't originally include in the schematics).

Daniel
by Daniel Wee
Wed 11 Mar 11 2009 2:21 am
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Well, the intermittent problem was reduced somewhat but it still shows up from time to time. It doesn't seem to have anything to do with the remaining buffer size. Neither does it seem to have anything to do with the _SS0 line either. So what we've now done, after instituting some safeguards in the ...
by Daniel Wee
Tue 10 Mar 10 2009 10:44 pm
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Okay, I admit a hardware debugger has its' uses. I've been struggling with this problem in the BOB-4 for a long long time and never did quite find the reason. Every now and then, when being pushed really hard, the system would hang and I would not know why. This would occur especially when the BOB-4...
by Daniel Wee
Tue 10 Mar 10 2009 5:04 pm
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Thinking about the screen-redraw rates raises a rather interesting issue. We are currently seeing full-screen redraws at a rate of about 15Hz and upwards. That's 15 screen redraws a second. But the BOB-4 datasheet says that it can only process 7kB/s of data. This means that as long as our 15 screen ...
by Daniel Wee
Tue 10 Mar 10 2009 3:17 pm
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Okay, all elements except for the alt-change arrow and the compass are done. With everything being rendered so far - a full screen takes around 58ms. This works out a to screen refresh rate of about 17.2Hz. We will need to see what happens when we render the compass as well but in practice, you won'...
by Daniel Wee
Tue 10 Mar 10 2009 1:32 pm
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Found another tricky one - it seems that the switching PSU is having some sort of ripples at start up that causes the BOB-4 to show some lines and occasionally fail to start up properly. I had to add a control for the RST line from RG15 to allow the DragonV2 to have direct control over the reset, af...
by Daniel Wee
Tue 10 Mar 10 2009 2:59 am
Forum: Projects
Topic: DragonPro
Replies: 20
Views: 15942

Re: DragonPro

Phew! That was some tricky stuff - the dsPIC33F is quite different from the dsPIC30F where ADCs concerned. Anyway, work done so far:- 1. Finally got the SPI routines to handle sending fast data to the BOB-4 without hanging 2. ADC with DMA finally working - voltage and current readings are working 3....