24FC64 EEPROM Running at 1Mhz ?

[jackberg1]

Thanks rsocor01 for the comment,

all I found was about 100Khz / 400Khz nothing that can run on the MSSP of Microchip 18F series.

same as I run with PBP3, Positron, Picaxe, I was interested to get an eeprom run at 1 Mhz from the Microchip AN989.

Using the MSSP Module to Interface I2C Serial EEPROMs with PIC18 Devices dated 2005

I figure that some of theses compilers will do the trick today in 2025

But no luck.

Maybe next year?....

[richard]

I figure that some of theses compilers will do the trick today in 2025


But no luck.


Maybe next year?....

the last time pbp had a new feature added space shuttles still had that new car smell about them

all the compilers that are not dead in the water already can support use of the mssp module

the link i posted explains nicely how to brew i2c commands using the mssp module and you can set the speed to 1mhz or even higher

you can tidy the i2c hardware process up a lot with "usercommand" if you're keen

[jackberg1]

Thanks Richard, I was looking if I made a mistake in my code, and get some help, sure the avenue of building the I2C, as you mention

it's interresting, I'll look at it see if I can get some result, also the test was made with an 24LC64, probably 400Khz,

the FC64 at 5Vcc, should run a 1Mhz , my assumption was that maybe my SFR was not setup properly, now I understand I have to 'Brew"

like you said my own function.

Thanks Richard for your advise

take care.

[tumbleweed]

In order to get 1MHz operation you'll likely have to reduce the SDA/SCL pullups to a lower value than you're typically used to.
The rise time of the open-drain signals will need to be faster than when you're working at 100K or 400K.

You might also consider an I2C risetime accelerator IC which will boost the current during the rising edge.
I've used these up to 800KHz with good success... much faster and the internal logic of the MSSP in the PIC18 tends to generate a bus collision (BCLIF) during the START bit.

If you're looking for a BASIC that supports MSSP operation up to 1MHz you might try Swordfish BASIC https://www.sfcompiler.co.uk/swordfish/

Since you don't really get a big performance boost running that much faster if you really want speed then switch to an SPI EEPROM.

[jackberg1]

Hello tumbleweed

About the resistor I used 2k for 1Mhz as for the AN989 even thought the test was done using an LC on that document.

It's not so easy to get the FC serie running from PBP3, so I'll stick to 400Khz.

thanks for your advice,