Avalon to external bus bridge - Accessing 8Bit with 32Bit commands

You may check https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/manual/mnl_avalon_spec.pdf page 36 for address alignment.

Basically,

a 32-bit master read from a 16-bit slave results in two read transfers on the slave side. The reads are to consecutive addresses.

To write to specific bytes within a data word, the master must use the byteenable signal. Page 14