I've used these displays in the past with success, and now I'm using two of them in parallel on the I2C bus and I can't figure out what's wrong. Each of the two displays has been assigned its own I2C address and they both work great if they are individually plugged in. However, when I plug them both in neither screen accepts any command and nothing is displayed. I've checked the waveforms on my scope and they are identical to the waveforms of the individual LCD operations. Therefore, I must conclude that neither slave device is holding any of the lines low. I've tried reducing my clock speeds down to well below 100kHz with no effect... I am completely at a loss as to how to debug this or where the problem even lies. Has anyone experienced this problem before or have any insight?
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