8440, 8470, Z8440, Z80SIO0, Z8470, Z80DART Z80 dual async/sync serial I/O. Z8470 has no synchronous capabilities. +--------------+ D1 |1 +--+ 40| D0 D3 |2 39| D2 D5 |3 38| D4 D7 |4 37| D6 /INT |5 36| /IORQ IEI |6 35| /CE IEO |7 34| A0 B/A /M1 |8 33| A1 C/D VCC |9 32| /RD /W_RDYA |10 Z8440 31| GND /SYNCA |11 SIO-0 30| /W_RDYB RxDA |12 29| /SYNCB /RxCA |13 28| RxDB /TxCA |14 27| /RxTxCB TxDA |15 26| TxDB /DTRA |16 25| /DTRB /RTSA |17 24| /RTSB /CTSA |18 23| /CTSB /DCDA |19 22| /DCDB CLK |20 21| /RST +--------------+ [This information is part of the GIICM]