Hi ALl,
I have a need to interface a PIC 18FXXJXX part to a serial EEPROM and was wondering if anyone have any sample routines that might help guide me in the right direction. I am familiar with I2C stuff, I just never have interfaced one to a PIC. Any thoughts or help would be appreciated.
Thanks
I2C Routine
Moderators: David Barker, Jerry Messina
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Jerry Messina
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Thanks
Hi Jerry,
Thanks once again. I had not thought to look there. So far I think I am going to target the 25LC640A or something similar. I wish I could find a RTC and EEPROM storage part in one, but so far I have not had any luck finding a chip like that. Worse case I find a seperate RTC part to go along with the EEPROM.
Thanks once again. I had not thought to look there. So far I think I am going to target the 25LC640A or something similar. I wish I could find a RTC and EEPROM storage part in one, but so far I have not had any luck finding a chip like that. Worse case I find a seperate RTC part to go along with the EEPROM.
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Jerry Messina
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>I wish I could find a RTC and EEPROM storage part in one
There are a number of devices like that, although you may not find one with as much eeprom as you want. Check out the MCP79410. Usually you get ~1K (bits) or so, but I'm sure there are others.
>I am going to target the 25LC640A
The 25xx series eeproms have an SPI interface. It's the 24xx series that are I2C
EDIT: it looks like a lot of the combo devices aren't made anymore. About the largest I could find were ~512 bytes (Dallas/Maxim DS1388 and Intersil ISL12026)
There are a number of devices like that, although you may not find one with as much eeprom as you want. Check out the MCP79410. Usually you get ~1K (bits) or so, but I'm sure there are others.
>I am going to target the 25LC640A
The 25xx series eeproms have an SPI interface. It's the 24xx series that are I2C
EDIT: it looks like a lot of the combo devices aren't made anymore. About the largest I could find were ~512 bytes (Dallas/Maxim DS1388 and Intersil ISL12026)
A RTC and storage part i've been using lately that may be useful to you has been the DS32C35.
I2C RTC with integrated TCXO & crystal and 8K Non-volatile FRAM.
FRAM means no-backup supply needed just like EEPROM, but it has no write cycle limits plus it's very fast to write!
TCXO means it seems to stay pretty darn stable too.
Rangerbob
I2C RTC with integrated TCXO & crystal and 8K Non-volatile FRAM.
FRAM means no-backup supply needed just like EEPROM, but it has no write cycle limits plus it's very fast to write!
TCXO means it seems to stay pretty darn stable too.
Rangerbob
SPI Mode
Hi Guys,
Thanks for the input. I actually meant I wanted to use SPI mode not I2C so hopefully there are some examples in the compiler for the 18F parts I can look at to get started. I ran across a MCP79410 part that has EEPROM and RTC in one SO-8 part, but I am not sure 128 bytes will be enough for me.
Thanks for the input. I actually meant I wanted to use SPI mode not I2C so hopefully there are some examples in the compiler for the 18F parts I can look at to get started. I ran across a MCP79410 part that has EEPROM and RTC in one SO-8 part, but I am not sure 128 bytes will be enough for me.
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Jerry Messina
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- Joined: Fri Jan 30, 2009 6:27 pm
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RangerBob's got a good point. Didn't think about FRAM.
Ramtron has some RTCC/FRAM parts with a lot of storage (up to 32K bytes) and either SPI or I2C interfaces. See http://www.ramtron.com/products/integra ... anion.aspx
It looks like the SPI ones are 3V parts
Ramtron has some RTCC/FRAM parts with a lot of storage (up to 32K bytes) and either SPI or I2C interfaces. See http://www.ramtron.com/products/integra ... anion.aspx
It looks like the SPI ones are 3V parts