So if we wish to read from the chip, our sequence would be as follows: Suppose I want to read some data from my EEPROM, what do I need to do with these pins to make it all work? Performing operations on EEPROM is all about doing things in the right order.
Always connect all the pins to your circuit! For example, RF interference may cause a high or low signal and therefore make the pin act as if it is enabled or disabled. Warning!!!: Leaving one of these pins disconnected from the circuit does not equal to it being pulled down! If any of the pins are left disconnected from the circuit we call them "floating" and essentially their state is random and undetermined. This may sound counter intuitive since you expect to pull up to turn on something but such is life sometimes. In some cases (and in our case in particular), pulling up a pin causes the corresponding state to be Disabled instead of Enabled. The jargon used for the operation is "pull up" for connecting to voltage and "pull down" for connecting to the ground. It is easy! Depending on your EEPROM chip, you enable or disable these pins by connecting them to a voltage source or to the ground. Depending on the type of chip, connecting it to ground or to voltage will make the chip write data to a selected memory address (more on that later). Write Enable is similar to Output Enable but used for writing data to the chip. Disabling the Output completes the read operation. Once again, depending on the chip, connecting this pin to the ground or to voltage will tell the chip to present you with the contents of given memory address (more on that later).
Output Enable is a pin used to tell the chip that you want to read from it. Disabling the chip allows us to power down the chip while leaving it electrically connected to our circuit. Needless to say, that if we want to perform any operation we need to enable the chip. Depending on the type of chip, connecting this pin to the ground or to voltage will turn the chip on or off. This is done using 3 control pins typically named Chip Enable, Output Enable and Write Enable.Ĭhip Enable controls whether or not the chip is powered up. In order to read, write and erase data from an EEPROM chip, we must first bring the chip at the correct state. This simple tutorial will guide users through the process of interfacing an EEPROM chip to a Raspberry Pi using the GPIO pins and performing operations with Python scripts.