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makerbase-mks / MKS-DLC32

MKS DLC32 motherboard kit, which is an offline engraving master control kit developed for desktop engraving machines. The hardware is equipped with a 32-bit high-speed ESP32 module, integrated WIFI function, and directly drives a 3.5-inch touch color screen; it can realize fast engraving and WEB web pages. Control, mobile phone APP control and other functions.
https://www.aliexpress.com/item/1005003183498253.html?spm=a2g0o.store_pc_home.productList_8356958.pic_0
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External Motor Driver Voltage #404

Open pionex opened 1 year ago

pionex commented 1 year ago

I am trying to drive external drivers, but I'm only seeing about 3.7v out of the external drive pins. When set to inverted drive mode, the logical low is 1.2v. Is there some reason this chip is not driving 0-5v? The 74HC595 chip has 5v on VCC, so I'm not sure why the output voltage is so low. This is measured with my scope and DMM with no load and nothing plugged into the rest of the board. Is this voltage normal?

pionex commented 1 year ago

It seems to me like this board should have a 74HCT595 (CMOS with TTL compatible inputs) instead of a 74HC595 (pure CMOS). I have replaced the chip on my board and now it works properly.