The data sheet states that GPxSET and GPxCLR have a default value of 0x000000XX, however these are write only, is this an error in the document, or can the port input values be read in the low byte, like in GPxDAT?
GPxSET and GPxCLR are write only registers which can't be read.
If you use GPxSET and GPxCLR registers, that means that the corresponding pins you want to configure are in output status in advance. Actually after configure the GPxSET and GPxCLR registers, you can read GPxDAT register bit[23:16] to check if the GPxSET and GPxCLR registers write correctly.
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