Electronic – SSD1306-based OLED display E/RD# and R/W# pins

datasheeti2coled

This is the OLED display in question and this is the datasheet of the display. I am going to connect to it using I2C.
The datasheet provides mostly understandable explanations for the pins as far as their usage in different communication modes (I2C,SPI,8 bit parallel etc.) goes.

These are a couple that I have trouble with:

Both of these pins have mentions of their function when driving them using using "68XX-series and 80XX-series microcontroller". From the datasheet it seems they mean 8-bit parallel com:

The question is, should leave them floating when using I2C? Or is data read still dependent on the state of those pins. I assume not, but I'd like to hear from someone who has had actual experience with them.

Best Answer

The question is, should leave them floating when using I2C?

Use this "ER-OLED0.96-1 Series Interfacing Document" from the display manufacturer's page which you linked.

It includes the following I2C interface schematic, which shows those two signals E/RD# and R/W# are both grounded when using I2C, as I've marked in red on this extract from that document:

Related Solutions

Adafruit SSD1306, I2C, ATmega1284p: OLED Display askew/misaligned

Update: I've now fixed the problem I was having with this - the problem in my case was caused because the page start and end address wasn't being set during initialisation. I've added the following command to the begin() function and now my displays are always correctly initialised.

// I was hitting a problem where the start line was not going back to zero during reset
// Setting the page start and end addresses seems to fix that.
command( 0x22 ); // Set page start and end addresses
command( 0x00 ); // start at zero
command (0x07) ; // end at seven.

Hope that helps someone out there... Took me forever to work it out.

Cheers!!

Electronic – Which interface is better for the OLED display

They are all comparable, with the tradeoffs being Pins vs Speed. It really boils down to your preference. How many free pins do you have (Can you spare 8 data + 4/5 control pins for parallel data?), are you already using SPI or I2C? The I2C version will limit you to only 2 lcds without using multiple I2C buses or buffers/switches, but only requires 3 data lines (SDA/SCL/Reset) and simplifies the command/data code by including it into a byte instead of requiring external pin toggling.

If you were me, I'd use i2c, but mostly because I prefer it. If you are already using SPI, that be the way to go.

As for 6800 vs 8080 lcd addressing, they are pretty similar, and have no performance difference. The 6800 interface is a bit easier to implement, and for the most part, is exactly the same as the common HD44780 character lcd interface.

Best Answer

Related Solutions

Adafruit SSD1306, I2C, ATmega1284p: OLED Display askew/misaligned

Electronic – Which interface is better for the OLED display

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