8xC251Tx Hardware Description

2
2.0 SIGNAL SUMMARY
Table 1. 8xC251Tx Signal Summary
Address & Data Input/Output
Name PLCC DIP Name PLCC DIP
AD0/P0.0 43 39 P1.0/T2 2 1
AD1/P0.1 42 38 P1.1/T2EX 3 2
AD2/P0.2 41 37 P1.2/EC/RXD1 4 3
AD3/P0.3 40 36 P1.3/CEX0/TXD1 5 4
AD4/P0.4 39 35 P1.4/CEX1 6 5
AD5/P0.5 38 34 P1.5/CEX2 7 6
AD6/P0.6 37 33 P1.6/CEX3/WAIT# 8 7
AD7/P0.7 36 32 P1.7/CEX4/A17/WCLK 9 8
A8/P2.0 24 21 P3.0/RXD 11 10
A9/P2.1 25 22 P3.1/TXD 13 11
A10/P2.2 26 23 P3.4/T0 16 14
A11/P2.3 27 24 P3.51/T1 17 15
A12/P2.4 28 25
A13/P2.5 29 26 Power & Ground
A14/P2.6 30 27 Name PLCC DIP
A15P2.7 31 28 VCC 44 40
P3.7/RD#/A16 19 17 VCC2 12
P1.7/CEX4/A17/WCLK 9 8 VSS 22 20
VSS1 1
Processor Control VSS2 23,24
Name PLCC DIP
P3.2/INT0# 14 12 Bus Control & Status
P3.3/INT1# 15 13 Name PLCC DIP
EA# 35 31 P3.6/WR# 18 16
RST 10 9P3.7/RD#/A16 19 17
XTAL1 21 18 ALE 33 30
XTAL2 20 19 PSEN# 32 29
NOTE: Pins in this font indicate functions associated w ith the second serial I/O port.