Character rom

[derek]

Hi,

Recently I have a MCU design problem. I have designed a electronic
device which can communicate with computer by ethernet to retrieve
data. And I want to include character ROM so that it can display
native characters. However, I have calculated the ROM size requirement
is about 2M bytes.

So the ROM must transfer data to the MCU serially as there are not so
many free pins at MCU side. For such a large ROM size with serial
interface I found only flash memory such as MMC card can do that.
However, because it is flash memory I need to read a minimum of one
sector which is 256 bytes for each character. This made the display
slow.

Actually I have thought to retrieve the font by the ethernet. However,
the menu cannot display correctly during offline and this brings a lot
of other problems.

Do anyone think another solution for me?

Thanks!

 

[Dave Garnett]

Atmel Dataflash

"derek" <dereklai2k@yahoo.com.hk> wrote in message
news:6bbcbd08.0412120422.39e4ccfa@posting.google.com...

Hi,

Recently I have a MCU design problem. I have designed a electronic
device which can communicate with computer by ethernet to retrieve
data. And I want to include character ROM so that it can display
native characters. However, I have calculated the ROM size requirement
is about 2M bytes.

So the ROM must transfer data to the MCU serially as there are not so
many free pins at MCU side. For such a large ROM size with serial
interface I found only flash memory such as MMC card can do that.
However, because it is flash memory I need to read a minimum of one
sector which is 256 bytes for each character. This made the display
slow.

Actually I have thought to retrieve the font by the ethernet. However,
the menu cannot display correctly during offline and this brings a lot
of other problems.

Do anyone think another solution for me?

Thanks!

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[Ziza]

"derek" <dereklai2k@yahoo.com.hk> wrote in message
news:6bbcbd08.0412120422.39e4ccfa@posting.google.com...

Hi,

Recently I have a MCU design problem. I have designed a electronic
device which can communicate with computer by ethernet to retrieve
data. And I want to include character ROM so that it can display
native characters. However, I have calculated the ROM size requirement
is about 2M bytes.

So the ROM must transfer data to the MCU serially as there are not so
many free pins at MCU side. For such a large ROM size with serial
interface I found only flash memory such as MMC card can do that.
However, because it is flash memory I need to read a minimum of one
sector which is 256 bytes for each character. This made the display
slow.

Actually I have thought to retrieve the font by the ethernet. However,
the menu cannot display correctly during offline and this brings a lot
of other problems.

Do anyone think another solution for me?

Thanks!
Why don't you try to compress data?

 

[John Woodgate]

I read in sci.electronics.design that Ziza <ziza69@hotmail.com> wrote
(in <cpimfd$36q$1@garrison.globalnet.hr&gt about 'Character rom', on Mon,
13 Dec 2004:

Recently I have a MCU design problem. I have designed a electronic
device which can communicate with computer by ethernet to retrieve
data. And I want to include character ROM so that it can display
native characters. However, I have calculated the ROM size requirement
is about 2M bytes.

Investigate the design of Teletext character ROMs. Made in the days when
2 MB was a dream.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

Sorry, the exact size should be about 700K bytes. The font is Chinese
which is 16x16.

 

I just calculate the total characters (22K) from Big5 table:
http://www.khngai.com/chinese/charmap/tblbig.php?page=0