MC68HC901 Datasheet, PDF (19/73 Pages) Motorola, Inc – Multi-Function Peripheral

Signal Description
Table 2-1. Signal Summary (Continued)
SIGNAL NAME
Data Transfer Acknowledge
Register Select Bus
Data Bus
Reset
Interrupt Request
Interrupt Acknowledge
Interrupt Enable In
Interrupt Enable Out
General Purpose I / O
Timer Clock
Timer Inputs
Timer Outputs
Serial Input
Serial Output
Receiver Clock
Transmitter Clock
Receiver Ready
Transmitter Ready
* Open Drain
MNEMONIC
DTACK
RS1 – RS5
D0 – D7
RESET
IRQ
IACK
IEI
IEO
I0 – I7
XTAL1
XTAL2
TAI, TBI
TAO, TBO,
TCO, TDO
SI
SO
RC
TC
RR
TR
INPUT/
OUTPUT
Output
Input
Input /
Output
Input
Output
Input
Input
Output
Input /
Output
Input
Output
Input
Output
Input
Output
Input
Input
Output
Output
ACTIVE
STATE
Low
N/A
N/A
Low
Low
Low
Low
Low
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Low
Low
THREE-
STATE
Yes
Yes
No*
No
Yes
No
No
Yes
No
No
RESET
STATE
High
Hi-z
High
High
Hi-Z
Low
Hi-Z
High
Low
2-6
MC68HC901 USER’S MANUAL
MOTOROLA