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Various ways to drive VGA display from serial stream

In November 2014, I became aware of the Hobbytronics.co.uk "SerialVGA", a small circuit to interface between any source of TTL serial data and an ordinary VGA monitor. Fifty lines of 100 characters. Multiple windows (with built in line-wrapping and scrolling).

I like it. I have explained more at a page dedicated to the Hobbytronics SerialVGA device.

Someone wrote me, and said, "What about the MicroVGA from http://www.microvga.com/?

Here are my thoughts. (I have played with the basic features of the Hobbytronics device, I have not played with the MicroVGA.)



The MicroVGA seems to have come out in or before 2009. Slightly dated system? And I didn't find a lot of discussion about it with Google.. which doesn't mean there's anything wrong with it. (The opposite, really... at least there weren't a lot of people complaining they'd sent money, received no goods!)... but I would have hoped for a bit more enthusiasm?

The MicroVGA can, which the SerialVGA can't, drive an "ordinary" TV. (Just to fill it with text... but it doesn't need a VGA monitor. But have you seen text on a TV screen? (Uses SVGA interface)

MicroVGA has Arduino libraries to allow you to use SPI to communicate with it. Use four pins instead of one? Doesn't make sense to me. Maybe this was for the days before ways to add serial ports to an Arduino? (And yes, you can drive the MicroVGA from an Arduino over a serial line... you don't HAVE to use the SPI alternative.)

MicroVGA has a socket into which you can plug a PS/2 keyboard. (The old keyboard/mouse protocol, not the games console!). But from forum posts, it seems that was a bit tricky (for some users, anyway) to get to work. Quite possibly user error... or maybe not. Review the posts, if you are buying a MicroVGA for the PS/2 interface.

SerialVGA has provision for a USB keyboard to be connected, but it does require an interface module. (11/14:£14) I haven't played with this option.

I found the MicroVGA site annoyingly coy about where the suppliers are based. Shipping terms usually give the game away... but these people have one flat rate for ALL destinations... and no guidance on how long it might take your board to arrive. They may be in the Czech Republic... where I have had good experiences with IT products. But not all firms in any country are the same, of course.

SerialVGA: 50 lines of 100 characters, 64 colors up to nine windows. Takes care of line-wrap and scrolling, one a window- by- window level. (You don't have to use windows.) Cost: £26. (11/14: about USD 40). Small, simple, mostly SMT board.

MicroVGA: 25 lines of 80 characters, 16 colors. No mention of windows. May or may not take care of line-wrap, scolling. (11/14: USD 30) More complex: Piggybacked boards, high component and connector count. Some of this, of course, due to addition opportunities. Some due to age.

MicroVGA: Allows Ascii-art. SerialVGA: Limited to standard Ascii characters (i.e. those with codes below 128) plus a few things for drawing boxes, putting bullets on lists, etc. Doesn't have the extended Ascii "blobs", etc, which were used in the heyday of Ascii-art.



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