单片机

8251
Universal asynchronous receiver/transmitter.
+-----+--+-----+
D2 |1 +--+ 28| D1
D3 |2 27| D0
RxD |3 26| VCC
GND |4 25| /RxC
D4 |5 24| /DTR
D5 |6 23| /RTS
D6 |7 8251 22| /DSR
D7 |8 21| RST
/TxC |9 20| CLK
/WR |10 19| TxD
/CE |11 18| TxEMPTY
C//D |12 17| /CTS
/RD |13 16| SYCDET BD
RxRDY |14 15| TXRDY
+--------------+

8253, 8254
Programmable interval timer/counter.
+-----+--+-----+
D7 |1 +--+ 24| VCC
D6 |2 23| /WR
D5 |3 22| /RD
D4 |4 21| /CE
D3 |5 20| A1
D2 |6 8253 19| A0
D1 |7 8254 18| CLK2
D0 |8 17| OUT2
CLK0 |9 16| G2
OUT0 |10 15| CLK1
G0 |11 14| G1
GND |12 13| OUT1
+--------------+

8255
Parallel Peripheral Interface.
+-----+--+-----+
PA3 |1 +--+ 40| PA4
PA2 |2 39| PA5
PA1 |3 38| PA6
PA0 |4 37| PA7
/RD |5 36| /WR
/CE |6 35| RST
GND |7 34| D0
A1 |8 33| D1
A0 |9 32| D2
PC7 |10 8255 31| D3
PC6 |11 30| D4
PC5 |12 29| D5
PC4 |13 28| D6
PC0 |14 27| D7
PC1 |15 26| VCC
PC2 |16 25| PB7
PC3 |17 24| PB6
PB0 |18 23| PB5
PB1 |19 22| PB4
PB2 |20 21| PB3
+--------------+

Z8530, Z8531
Zilog Serial Communications Controller.
Z8531 has no synchronous capabilities.
+-----+--+-----+
D1 |1 +--+ 40| D0
D3 |2 39| D2
D5 |3 38| D4
D7 |4 37| D6
/INT |5 36| /RD
IEO |6 35| /WR
IEI |7 34| A0 A/B
/INTAK |8 33| /CE
VCC |9 32| A1 D/C
/W_REQA |10 Z8530 31| GND
/SYNCA |11 SCC 30| /W_REQB
/RTxCA |12 29| /SYNCB
RxDA |13 28| /RTxCB
/TRxCA |14 27| RxDB
TxDA |15 26| /TRxCB
/DTR_REQA |16 25| TxDB
/RTSA |17 24| /DTR_REQB
/CTSA |18 23| /RTSB
/DCDA |19 22| /CTSB
CLK |20 21| /DCDB
+--------------+

8574, 8574A
I2C parallel I/O expander.
I2C address is 0100xxx for the 8574 and 0111xxx for the 8574A, where xxx can be specified by the A0-2 inputs.
+---+--+---+
A0 |1 +--+ 16| VCC
A1 |2 15| SDA
A2 |3 14| SCL
P0 |4 13| /INT
P1 |5 8574 12| P7
P2 |6 11| P6
P3 |7 10| P5
GND |8 9| P4
+----------+

8584
I2C bus controller.
Bus controller ties to either Z80-style bus or to 68000-style bus, and determines the mode from the first few cycles.
+---+--+---+
CLK |1 +--+ 20| VCC
SDAo SDA |2 19| /RST /STB
SCLo SCL |3 18| /WR R//W
SDAi /IACK |4 17| /CS
SCLi /INT |5 16| /RD /DTACK
A0 |6 8584 15| D7
D0 |7 14| D6
D1 |8 13| D5
D2 |9 12| D4
GND |10 11| D3
+----------+

16450
Asynchronous seria l interface controller.
+-----+--+-----+
D0 |1 +--+ 40| VCC
D1 |2 39| /RI
D2 |3 38| /DCD
D3 |4 37| /DSR
D4 |5 36| /CTS
D5 |6 35| MR
D6 |7 34| /OUT1
D7 |8 33| /DTR
RCLK |9 32| /RTS
RxD |10 16450 31| /OUT2
TxD |11 8250 30| INTR
CE0 |12 29|
CE1 |13 28| A0
/CE2 |14 27| A1
/CLKOUT |15 26| A2
X1 |16 25| /ADS
X0 |17 24| CSOUT
/WR |18 23| DDIS
WR |19 22| RD
GND |20 21| /RD
+--------------+

16550
Asynchronous serial interface controller with DMA support and 16-byte FIFOs.
+-----+--+-----+
D0 |1 +--+ 40| VCC
D1 |2 39| /RI
D2 |3 38| /DCD
D3 |4 37| /DSR
D4 |5 36| /CTS
D5 |6 35| MR
D6 |7 34| /OUT1
D7 |8 33| /DTR
RCLK |9 32| /RTS
RxD |10 16550 31| /OUT2
TxD |11 30| INTR
CE0 |12 29| /RXRDY
CE1 |13 28| A0
/CE2 |14 27| A1
/CLKOUT |15 26| A2
X1 |16 25| /ADS
X0 |17 24| /TXRDY
/WR |18 23| DDIS
WR |19 22| RD
GND |20 21| /RD
+--------------+

16552
Dual asynchronous serial interface controller with DMA support and 16-byte FIFOs, and an 8-bit parallel printer port.
PLCC68
+---------------+---------------+---------------+---------------+
| 10 2TxD | 27 GND | 44 1BD | 61 /2RXRDY |
| 11 /2DTR | 28 /1CTS | 45 1INT | 62 2RxD |
| 12 /2RTS | 29 /1DCD | 46 PD7 | 63 /ERR |
| 13 /2CTS | 30 /1RI | 47 PD6 | 64 VCC |
| 14 D0 | 31 /1DSR | 48 PD5 | 65 SLCT |
| 15 D1 | 32 /1CE | 49 PD4 | 66 BUSY |
| 16 D2 | 33 A2 | 50 PD3 | 67 PE |
| 17 D3 | 34 A1 | 51 PD2 | 68 /ACK |
| 18 D4 | 35 A0 | 52 PD1 | 1 PEMD |
| 19 D5 | 36 /WR | 53 PD0 | 2 2TR |
| 20 D6 | 37 /RD | 54 GND | 3 /2CE |
| 21 D7 | 38 /PCE | 55 /STB | 4 CLK |
| 22 /1TXRDY | 39 /RST | 56 /AFD | 5 /2DSR |
| 23 VCC | 40 VCC | 57 /INIT | 6 /2RI |
| 24 /1RTS | 41 1RxD | 58 /SLIN | 7 GND |
| 25 /1DTR | 42 /2TXRDY | 59 PINT | 8 /2DCD |
| 26 1TxD | 43 /ENIRQ | 60 2INT | 9 /1RXRDY |
+---------------+---------------+---------------+---------------+