OLED I2C Silkscreens are wrong, or are they?

RE: OLED I2C Silkscreens are wrong, or are they?

jc2048 — Sun, 07 Feb 2021 10:00:54 GMT

The confusion was baked into the original spec.

[View:/resized-image/__size/620x329/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41d686a0-e69a-4f4e-9a97-f87b17cb22ee/3323.contentimage_5F00_207326.jpg:620:329]

On datasheets at that time, Philips used the byte format. Here's an example of a device with addresses 0x8A or 0x8E:

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41d686a0-e69a-4f4e-9a97-f87b17cb22ee/6765.contentimage_5F00_207327.jpg:620:465]

When writing code, I always stored the address as a byte (with the lsb 0) because I was familiar with the datasheets and it seemed more logical for a byte protocol.

For your OLED board, there's no right answer. But if they want to sell loads to makers and hobbyists using Arduino libraries, they'd probably do better to ignore datasheets and do it the way the programmer of the library did.

RE: OLED I2C Silkscreens are wrong, or are they?

Jan Cumps — Sat, 06 Feb 2021 22:58:37 GMT

Consistency in i2c address specification is not-a-thing [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41d686a0-e69a-4f4e-9a97-f87b17cb22ee/contentimage_5F00_1.png:16:16].

In a datasheet, an indication may be if they give a different address for read and write (->the 8 bits address) or not (->7bits).

What also not helps is that you look in example code and some HALs expect the 7-bit address, while others the distinct 8-bit read and write ones.

No matter how careful you are, it'll bite you once so often ...

RE: OLED I2C Silkscreens are wrong, or are they?

kmikemoo — Sat, 06 Feb 2021 20:34:38 GMT

[mention:57a79c8ceae84c06b59d42e67a0ded50:e9ed411860ed4f2ba0265705b8793d05] Bit banging to an answer is always cool. Thanks for sharing it.