80C18xEC Unused Pin Connections

80C186EC (80C188EC) Minimum Circuit Configuration*
Pin Name	Connection	Pin Name	Connection
Vcc**	+5V +-10%	T1OUT	N.C.
Vss**	Ground	T0IN	pulled high
CLKIN	2x CPU Clock	T1IN	pulled high
OSCOUT	N.C if using canned oscillator, connected to crystal otherwise	INT7:0	pulled low
CLKOUT	N.C.	INTA#	N.C.
RESIN#	reset circuit	P3.5,4	pulled low
RESOUT	N.C33	P3.3/DMAI1	N.C.
PDTMR	N.C.	P3.2/DMAI0	N.C.
NMI	pulled low	P3.1/TXI1	N.C.
TEST#/Busy	pulled high	P3.0/RXI1	N.C.
A19/S6/ONCE#	weekly pulled high	WDTOUT	N.C.
S2:0#	N.C.	P2.7/CTS1#	pulled low
READY	pulled high	P2.3/CTS0#	pulled low
Lock#	N.C.	P2.6/BCLK1	pulled low
Hold	pulled low	P2.2/BCLK0	pulled low
HLDA	N.C.	P2.5/TXD1	N.C.
NCS#	N.C.	P2.1/TXD0	N.C.
ERROR#	strap to Vcc	P2.4/RXD1	pulled low
PEREQ	strap to Vss	P2.0/RXD0	pulled low
P1.0/GCS0#:P1.7/GCS7#	N.C.	DRQ3:0	N.C.
INTA#	N.C.	N.C.	No Connect
T0OUT	N.C.

"Minimum circuit" implies a very basic prototype which allows the boot-up of the processor for testing purposes. It is assumed that none of the internal peripherals are being used. If they are to be used, some of the above connections might need to be changed. Pins missing from the table are assumed to be used in the minimum circuit memory interface. Please see the most current data sheet and User's Manual for a full description of each pin.

Pins specified as "pulled high" or "pulled low" can be strapped instead. Using pull-up or pull-down resistors instead of strapping makes design changes easier and less costly. Typical pull-up or pull-down resistors are 10 Kohms in size. Weak pull-up or pull-down resistors are typically 50 Kohms in size.

All "N.C." pins must remain unconnected.

**All of the Vcc and Vss pins present on the processor package must be connected to +5V +-10% and Ground respectively.