Difference between revisions of "VGA Shield"

From Hackstrich
(Pogo pins are too expensive.)
(Final list of issues with rev 1.)
Line 5: Line 5:
  
 
== Design Overview ==
 
== Design Overview ==
 +
* Using uVGA-II(SGC) module from 4D Systems to generate video
 
* Shield will provide I2C-RS232 bridge so the Arduino doesn't have to use its (only) RS232 UART for this
 
* Shield will provide I2C-RS232 bridge so the Arduino doesn't have to use its (only) RS232 UART for this
 
* Will provide a 3.5mm jack for external speakers (no room on shield for a speaker)
 
* Will provide a 3.5mm jack for external speakers (no room on shield for a speaker)
 
* The µVGA-II(SGC) has 16 GPIOs, so will pin those out on the standard 2x5 connectors
 
* The µVGA-II(SGC) has 16 GPIOs, so will pin those out on the standard 2x5 connectors
 
* Status LEDs for power, TX, RX, and audio enabled
 
* Status LEDs for power, TX, RX, and audio enabled
−
 
−
== Chipset Options ==
 
−
* 4D Systems µVGA-PICASO-MD1 module ($54)
 
−
** Very expensive
 
−
** Some complaints about reliability
 
−
** Only talks RS232
 
−
 
−
* '''New 4D Systems uVGA-II(SGC) module ($49)'''
 
−
** Relatively expensive
 
−
** Only supports up to 800x480 (WVGA) @ 16bpp
 
−
** Very easy to interface with (via an I2C/SPI to RS232 bridge likely)
 
−
 
−
* Propeller chip with custom code ($8)
 
−
** Cheap
 
−
** Unsure how high resolution would be possible given generating VGA video from an MCU
 
−
 
−
* Custom FPGA solution ($?)
 
−
** More work than any other solution
 
−
** Similar cost to propeller chip, likely
 
−
 
−
* Off-the-shelf VGA controller chip
 
−
** The Epson S1D13506 seems promising, you talk to it and it has an internal RAMDAC to generate video.
 
−
*** Supports LCD, VGA, and NTSC/PAL composite output
 
−
*** Flexible bus to talk to the microcontroller
 
−
*** Requires EDO DRAM, which isn't available anymore.
 
−
** The Epson S1D13517 might work, it's like the S1D13506 but takes SDRAM
 
−
*** Supports up to 800x600 16bpp
 
−
*** Only supports TFT displays, may be able to make it talk DVI though through timings/TMDS converter?
 
−
 
−
* [[Project Peacock]]
 
−
** Hybrid CPLD/MCU solution, cheaper than using a softcore in an FPGA
 
−
** Would allow for an easy DVI shield too
 
  
 
== Revision 1 Issues ==
 
== Revision 1 Issues ==
Line 49: Line 18:
 
*** Would add $10 to the shield, eek!
 
*** Would add $10 to the shield, eek!
 
** Connector on wires?
 
** Connector on wires?
 +
** Small adapter PCB?
 +
** Mod each shield with straight pins aiming down?
 
* Pads on audio jack could be a bit larger to make it easier to inspect soldering
 
* Pads on audio jack could be a bit larger to make it easier to inspect soldering
 +
* Audio Enable is actually an OUTPUT from the module, not an input like the datasheet says
 +
** Rev. 2 should remove the two solder jumper sets from this pin, but retain the LED for Audio On
 +
* Audio On, RX, and TX LEDs are all backwards (on = idle), need to hook them up to +3.3v instead of GND and flip them
 +
* Can't get audio working at all
 +
** Left support request for 4D, suspect a bug/mis-documentation in the module
 +
* LEDs for TX/RX are dim, should change to the ones used on the MultiSerial shield for part commonality and because they work better
 +
* Spacing on the two GPIO headers doesn't work well, shrouded ones won't fit and two IDC ribbon connectors side by side won't fit and it blocks the microSD slot
 +
** Be careful on layout as the microSD card slot on the VGA module needs to be accessible
  
 
[[Category:Projects]]
 
[[Category:Projects]]
 
[[Category:Current Projects]]
 
[[Category:Current Projects]]
 
[[Category:Status/Waiting for Parts]]
 
[[Category:Status/Waiting for Parts]]

Revision as of 18:42, 20 March 2011

The VGA Shield will be, as the project name may indicate, an Arduino-compatible shield that outputs VGA video.

Project Status

Schematic and board layout complete, PCBs received, VGA modules received from 4D, parts received from Digikey. First rev. 1 board has been assembled and is working fine video-wise. Testing continues.

Design Overview

  • Using uVGA-II(SGC) module from 4D Systems to generate video
  • Shield will provide I2C-RS232 bridge so the Arduino doesn't have to use its (only) RS232 UART for this
  • Will provide a 3.5mm jack for external speakers (no room on shield for a speaker)
  • The µVGA-II(SGC) has 16 GPIOs, so will pin those out on the standard 2x5 connectors
  • Status LEDs for power, TX, RX, and audio enabled

Revision 1 Issues

  • Through-holes for all connectors mating with the VGA module are too small!
    • Worked around for rev. 1 by modifying VGA module w/ thinner machine pins
  • Serial connector doesn't work well at all, need to figure out a better solution for rev. 2
    • Concave pogo pins?
      • Would add $10 to the shield, eek!
    • Connector on wires?
    • Small adapter PCB?
    • Mod each shield with straight pins aiming down?
  • Pads on audio jack could be a bit larger to make it easier to inspect soldering
  • Audio Enable is actually an OUTPUT from the module, not an input like the datasheet says
    • Rev. 2 should remove the two solder jumper sets from this pin, but retain the LED for Audio On
  • Audio On, RX, and TX LEDs are all backwards (on = idle), need to hook them up to +3.3v instead of GND and flip them
  • Can't get audio working at all
    • Left support request for 4D, suspect a bug/mis-documentation in the module
  • LEDs for TX/RX are dim, should change to the ones used on the MultiSerial shield for part commonality and because they work better
  • Spacing on the two GPIO headers doesn't work well, shrouded ones won't fit and two IDC ribbon connectors side by side won't fit and it blocks the microSD slot
    • Be careful on layout as the microSD card slot on the VGA module needs to be accessible
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