MC68HC901 Datasheet, PDF (12/73 Pages) Motorola, Inc – Multi-Function Peripheral

Introduction
1.1 KEY FEATURES
The MFP performs many of the functions common to most microprocessor-based systems.
The resources available to the user include:
• Eight individually programmable I/O pins with interrupt capability
• 16-source interrupt controller with individual source enable and masking
• Four timers, two of which are multi-mode timers
• Single-channel full-duplex universal synchronous/asynchronous receiver-transmitter
(USART) which supports:
— asynchronous formats
— byte synchronous formats, with the addition of a polynomial generator checker
By incorporating multiple functions within the MFP, the system designer retains flexibility
while minimizing device count.
1.2 REGISTER PROGRAMMING
From a programmer's point of view, the versatility of the MFP may be attributed to its register
set. The registers are well organized and allow the MFP to be easily tailored to a variety
of applications. All of the 24 registers are also directly addressable which simplifies
programming. The register map is shown in Table 1-1.
Table 1-1. MFP Register Map
ADDRESS
HEX
BINARY
ABBREVIATION
REGISTER NAME
RS5 RS4 RS3 RS2 RS1
01
0
0
0
0
0
03
0
0
0
0
1
05
0
0
0
1
0
07
0
0
0
1
1
09
0
0
1
0
0
0B
0
0
1
0
1
0D
0
0
1
1
0
0F
0
0
1
1
1
11
0
1
0
0
0
13
0
1
0
0
1
15
0
1
0
1
0
GPDR
AER
DDR
IERA
IERB
IPRA
IPRB
ISRA
ISRB
IMRA
IMRB
General Purpose I / O Data Register
Active Edge Register
Data Direction Register
Interrupt Enable Register A
Interrupt Enable Register B
Interrupt Pending Register A
Interrupt Pending Register B
Interrupt In-service Register A
Interrupt In-service Register B
Interrupt Mask Register A
Interrupt Mask Register B
1-2
MC68HC901 USER’S MANUAL
MOTOROLA