May 21, 2007
News - Arduino: The Documentary
about 4 years ago
Seriously, Motopic, FPGA’s and low-end MCU’s are just not the same thing.
I can show you stuff you could NEVER do on any MCU in realtime. But you can on an FPGA.
While at the same time, I could show you stuff that’s just not worth doing on an FPGA because the need for speed is not there or it’s a hassle.
MCU’s and FPGA’s have their niches… otherwise they wouldn’t both exist and have flourishing markets.
Also, to program FPGA’s does require another language… unless you’ve never learned to use MCU’s before, then you have to learn another language. And they do have FPGA compilers that take C (although I’ve only authored FPGA’s in VHDL & Verilog)
Xilinx ISEwebpack - Free. (and a good HDL Compiler)
OpenCores.Org - Free (or darn close)
UARTs, I2C, SPI all available from somewhere - Free.
Spartan3E’s can be had for a little under $10ea in low qty.
Microchip: MPLAB - FREE.
MPLAB also includes lite compilers from hi-tech and CCS for FREE. Not to mention the student editions of C18-C32 (free).
about 4 years ago
This display is completely pin compatible with the original (that used the ssd1339 driver), however it does not support 8 bit (256 color) mode, and therefore must have 2 bytes of color data sent over its 8 bit interface. If possible, get the version of this display that has the full 16/18 bit interface as the lack of 256 color mode causes a drop in performance (as compared to the one with ssd1339) that you cannot help. That being said, I have used this display with the arm7 (2148) and am happy with it. If anyone wants, I can post a link to my driver code which has many different drawing functions and a few different text sizes.
In looking at the 2 datasheets though, note the top speed for the 1339 in serial mode is 250nS (5MHz) while the 1351’s top speed for the serial is 50nS (20MHz). For the 1351, a complete sequence is 400nS + overhead VS the parallel mode where a complete sequence is 300nS+overhead. Yes it adds up – but it’s still a lot better than the 1339 where serial would be 2uS per byte vs 300nS per byte (plus overhead).
As I mentioned already, I’ve been running the unit at about 2.6MHz and for text stuff in 16bit color mode. It’s not too bad. Oddly, I tested my 1339 @ 10MHz and it seemed to work ok (although I wouldn’t recommend this for normal operation.)
If your micro can do an SPI rate of 20MHz, hey, that could be ok too depending on WHAT you’re doin. :D
But I thought I’d mention the numbers.
For anyone interested,
I’m just finishing up a PIC18F based interface to the SSD1339 (and will probably end up writing support for the 1351).
Seeing how the SSD1339 based unit is gone, I decided to check the performance in SPI mode with 16bit color. For text it’s ok. The screen refresh speed is evident, but for a colorized text display without whole-screen moving graphics, it’s still not bad in SPI mode (at 2.6Mb/s)
The SSD1339’s accelerated commands are nice though. Too bad the 1351 doesn’t have ‘em.
No public wish lists :(
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