code: def write_PIA0_A_data(self, cpu_cycles, op_address, address, value):
          
          log.error("%04x| write $%02x (%s) to $%04x -> PIA 0 A side Data reg.\t|%s",
              op_address, value, byte2bit_string(value), address,
              self.cfg.mem_info.get_shortest(op_address)
          )
          self.pia_0_A_register.set(value)
docs: write to 0xff00 -> PIA 0 A side Data reg.