writing only LSB to 16Bit port

on7nh · Joined: 05 Jun 2006 Posts: 41 Location: Belgium

hello,
Is it possible to write only the lower 8 bits to a 16 bit port (CPU is DSPIC30f6014a) ?

I want to write data to the lower 8 bits, and leave the state of the higher 8 bits at its actual state.

Ttelmah · Joined: 11 Mar 2010 Posts: 19360

Should be easy. Since the chip supports a byte wide write. On a lot of '16bit' chips, this is impossible (they only do a 16bit I/O operation to the ports), and on these you have to read the whole word, mask in the new bits you want, and write the word back. On the PIC30 though a byte wide write is supported. So: