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match0927
Joined: 26 May 2009
Posts: 3
Location: Halifax, Nova Scotia, Canada
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| treat MMC card as a big EEPROM |
 Posted: Tue May 26, 2009 8:48 am |
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| If I just wanna use MMC card as an EEPROM. e.g. just read or write a byte to some address. Is there a simple code to implement? I do not need create a file on the card then read it via the PC. Thanks. |
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asmallri
Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia
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| Re: treat MMC card as a big EEPROM |
| Posted: Tue May 26, 2009 9:48 pm |
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| match0927 wrote: | | If I just wanna use MMC card as an EEPROM. e.g. just read or write a byte to some address. Is there a simple code to implement? I do not need create a file on the card then read it via the PC. Thanks. |
You just need the basic low level SPI drivers. You need to take into account that unlike an EEPROM you cannot just change the location of a single byte but instead must read in the target sector into RAM (512 bytes) modify one or more bytes of interest, then write back the modified sector. Another important consideration is that the write endurance of an EEPROM is orders of magnitude higher than an MMC card.
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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Guest
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| Re: treat MMC card as a big EEPROM |
| Posted: Wed May 27, 2009 6:19 am |
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| asmallri wrote: | | match0927 wrote: | | If I just wanna use MMC card as an EEPROM. e.g. just read or write a byte to some address. Is there a simple code to implement? I do not need create a file on the card then read it via the PC. Thanks. |
You just need the basic low level SPI drivers. You need to take into account that unlike an EEPROM you cannot just change the location of a single byte but instead must read in the target sector into RAM (512 bytes) modify one or more bytes of interest, then write back the modified sector. Another important consideration is that the write endurance of an EEPROM is orders of magnitude higher than an MMC card. |
So is there such a kind of code here? Very thanks? |
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arunb
Joined: 08 Sep 2003
Posts: 492
Location: India
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| RE: |
| Posted: Fri May 29, 2009 4:21 am |
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| Quote: |
Another important consideration is that the write endurance of an EEPROM is orders of magnitude higher than an MMC card |
Do this mean MMC will wear out faster than EEPROM ??
thanks
arunb |
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asmallri
Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia
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| Re: RE: |
| Posted: Fri May 29, 2009 6:56 am |
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| arunb wrote: | | Quote: |
Another important consideration is that the write endurance of an EEPROM is orders of magnitude higher than an MMC card |
Do this mean MMC will wear out faster than EEPROM ??
thanks
arunb |
Yes.
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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