Hello,
Let us put here some practical info about driving the PSP 480x272 LCD using a Seiko controller. So anybody having success in displaying “Hello” on the PSP 480x272 LCD using a Seiko controller is warmly welcome here !
hello steph,
I never used the 480x272 Lcd with epson-seiko controllers … but some years ago i used the sed1375 to drive a 320x240 stn lcd.
From that experience i changed my idea to use a commercial controller to drive tft and stn…
This because of the full cpu bus needed by these chips …
So i developed a small verilog program to fit my need for a Lattice cpld (MachXO256, qfp100) + a 128K external static ram.
I tested it with a 480x272 but only at 16colors …
With this kind of device (cpld) it’s funny because you can to change the cpu interface, from 8bit parallel host, to 16bit muxed bus … to … spi …
I made a small test board and now we are making a new small board useful to test the touch panel …
So , if you don’t need to show photos , i think a so simple solution could be enough to start development of simple user interface
Hello enrico_c,
“small verilog” ? SPI interface ? What a nice job !
Screen updates can be quite fast with a SPI 1/4 cpuclk using a 72 Mhz processor ! Have you tried it ?
Colour should be at least 18 bits. Can you use three separate RAMs, maybe not all 8-bits being used in the first revision, on a multiplexed bus like the early EF9365 controllers from Thomson ?
Do you know Philippe Matherat, the man who designed the EF9365 back in 1978 ?
I wish your design (including the description of all the worries you needed to solve in an elegant way) could find his way in Elektor, with some background or history material coming from a Philippe Matherat interview. Interested ?
hello steph,
some pratical math: 480x272 = 130560pixelx…
a good tipical solution could be max 16bpp = 130560*2= 261120 bytes
you will need a 512K flash controller only to store 1-2 full video images …
using a dma and a SPI @18Mhz you can send to the video-ram about 2250bytes every 1msec … so, to store 261120bytes /2250= you will need more than 116msec for a full page image.
the rgb could be r=6, g=6; b=4, or r=6, g=5, b=5
to keep at least one video page i need a standard ram with 256x16bit
since the panel frequ. ins not more than 10Mhz we can use not more than 40-50% of the ram bandwidth running the cpld @50Mhz
Actually i’m usign 9bit for the lcd signals … r=3, g=3, b=3 useful to obtain more than 256combination …
With this reduction i can use a small 100pin qfp device …
Adding more ram and lcd bits requires a 144pin qfp cpld … quite larger …
I don’t know Philippe Matherat … and Elektor …
i think it is a magazine …
http://www.elektor.it/products/magazines.260.lynkx
but i do not think they can be interested to publish an hand soldered prototype / support demo board .
May be i can make a more friendly board (no hand sold wires for backlt or touch, standard power connectors, wide range power supply, etc) with all connectors for 4.3"TFT useful to create a generic kit-module.
With the programmed cpld everybody can solder and start the kit.
like this…
http://www.elektor.it/products/kits-mod … 1183.lynkx
i can try to ask …