The push-pull output driver is shown in Figure 9-48. The output buffer has a UARTTX_RO source resistance. The supply voltage to the system side buffer is configurable to be LDO_3V3 by default or VDDIO. This is not shown in Figure 9-48. The supply voltage to the port side buffers remains LDO_3V3.
Figure 9-48 IOBUF_UTX Output Buffer