| ??? 11/06/08 22:20 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#159861 - Richard, you flooded Bert's connection... Responding to: ???'s previous message |
... he said he's on wireless now...
Richard Erlacher said:
A mid-sized CPLD, e.g. XC2C256, or a small FPGA, e.g. XC3S150 or thereabouts should be quite suitable, I think this is the core of your message. For LCDs, you don't need a DAC, the input is pure digital (5-6 wires per color). So you just need a sequencer producing incremental address and the syncs; a memory (a.k. framebuffer); and glue logic to be able to access that memory from both the sequencer and the microcontroller (this is usually the toughest part); plus maybe some output buffers. The 6845 is not usable without significant glue logic - it's basically just the sequencer, and also it's low speed (2MHz max), so at least 2 bits of address have to be sequenced "externally". It is definitively doable - it's none more complex than a CGA graphics of which it was a constituent - but a bit out of date (not to mention that the youngest 6845 you can get nowadays is out of factory at least for 20 years). So, nowadays it seems to be easier to put both the sequencer and the glue into the CPLD/FPGA; however, it might be easier and faster to get a dedicated chip, which contains also the RAM (see the link to Epson devices I gave above). JW |
| Topic | Author | Date |
| How do you drive a RGB color LCD display? | 01/01/70 00:00 | |
| Look for processors or display controllers | 01/01/70 00:00 | |
| Search? | 01/01/70 00:00 | |
| Epson | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Back to basics | 01/01/70 00:00 | |
| Richard, you flooded Bert's connection... | 01/01/70 00:00 | |
| It's not as easy as one might think | 01/01/70 00:00 | |
| ready-made device | 01/01/70 00:00 | |
| buy an evaluation board | 01/01/70 00:00 | |
| a quick peek into the code library | 01/01/70 00:00 | |
That's what I would recommend | 01/01/70 00:00 |