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MVS-99-6 - Project on hold until further notice (2014-03-10)
Yvan256:
Stage 1 Complete: Display bitmap from internal memory
:cheers:
I'll need to work a bit on the display routines to make it faster (takes about 1/4 of a second right now) but otherwise it's working fine.
The viewing angle is also better from a bit below the connector, so I'll simply invert the image display routine and install it upside-down inside the marquee holder of the cabinet.
The photos really don't do it justice, it's as clean as the LCD monitor you're probably using right now to view this web page. There's no moiré pattern in real life, it's probably due to the grids of the LCD pixels and the CCD of the camera.
I had a bit of space left*, that's why I added the "Apple boot screen" image.
* actually the code space is only 27.3% full even with these two RLE-compressed TGA files embedded inside the code.
Stages:
- Stage 1A: Write pixels on LCD
- Stage 1B: Hardware SPI communication with the LCD/microSD
- Stage 1C: Functions to write ASCII characters on the LCD
- Stage 2: microSD raw blocks card access
- Stage 3: FAT16 microSD card access
- Stage 4: Serial communication with a computer
Nephasth:
Good stuff! Can't wait to see it in action in the marquee! :applaud:
Yvan256:
I can't wait either, in the meantime here's a crappy black and white laser printed marquee on top of the LCD. ;)
Here's an update on my LCD mini-marquee progress (one of the most complex part of the build):
- Write pixels on LCD in 18-bit mode
- Hardware SPI communication with the LCD/microSD (success - it's a lot faster than software SPI)
- Decode and display compressed 24-bit TGA graphics (still need to add a bit of error-checking for size, format, etc)
- Functions to write ASCII characters on the LCD (to display error messages such as "TGA file dimensions too big", "no microSD card present", etc and to help debug the microSD raw/FAT16 access and the serial communication later)
- microSD raw blocks card access
- FAT16 microSD card access
- Serial communication with a computer
Yvan256:
I hit another tiny problem: the LCD for the mini-marquee is going to be "trapped" inside the marquee holder at the top and bottom so I won't have access to its built-in microSD card socket.
No problem, since I already had ordered an SD card breakout board from Sparkfun, so I'll be able to have the SD card socket exactly where I want it behind the printed part of the marquee. It's also going to make it easier to find a smaller capacity, lower cost SD card because 1GB would be a waste. 100 marquees (99 games marquees + generic MVS marquee) will require at most 6MB. Hopefully I'll be able to find a 32MB card, 32MB being the smallest capacity allowed for FAT16 if I remember correctly.
But that tiny protoboard you've seen in the previous photo was too tiny to add anything else. So, I've transfered the whole thing to a bigger protoboard (see first photo).
I've also added a 3.3V regulator since the whole thing is going to be powered by 5V but the SD cards requires 3.3V only. Yes, I know, the wiring is a bit messy at the moment. The weird thing is, the ATmega644P is powered at 3.3V but still clocked at 20MHz. According to the datasheet it shouldn't even work. Not sure if it's damaging it but so far it's working fine.
Since this SD card socket has a "card detect" pin I've also added a routine for that. My error messages are on a black background with a 1-character margin all around it, centered in the display. It looks better this way IMHO.
Other error messages are going to be about wrong TGA files ("TGA image is bigger than display", "TGA image is in the wrong format", etc).
edit: small note, I just did a test with a "pattern" image like on my previous LCD and this new one is indeed 128x160 pixels, no rows or columns missing (previous one was listed as 132x132 but was actually only 130x130 visible pixels).
Nephasth:
WOW. That SD card next to the LCD really puts the size into perspective. TINY!
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