如题。引脚高电平是3.3v，直接接usb转串口。接收无问题

]]>https://bbs.aw-ol.com/topic/6806/v821-pl4和pl5串口0发送数据时-发送引脚低电平不能拉低到0导致发送失败RSS for NodeMon, 14 Sep 2026 11:39:39 GMTTue, 23 Dec 2025 08:09:27 GMT60