code: def read_PIA0_B_data(self, cpu_cycles, op_address, address):
          
          value = self.pia_0_B_data.value  # $ff02
          log.debug(
              "%04x| read $%04x (PIA 0 B side Data reg.) send $%02x (%s) back.\t|%s",
              op_address, address, value, byte2bit_string(value),
              self.cfg.mem_info.get_shortest(op_address)
          )
          return value
docs: read from 0xff02 -> PIA 0 B side Data reg.
  
          bit 7 | PB7 | keyboard matrix column 8
          bit 6 | PB6 | keyboard matrix column 7 / ram size output
          bit 5 | PB5 | keyboard matrix column 6
          bit 4 | PB4 | keyboard matrix column 5
          bit 3 | PB3 | keyboard matrix column 4
          bit 2 | PB2 | keyboard matrix column 3
          bit 1 | PB1 | keyboard matrix column 2
          bit 0 | PB0 | keyboard matrix column 1
  
          bits 0-7 also printer data lines