Intel 8XC196NT User Manual page 8

6.3.3 Bidirectional Port Pin Configuration Example .........................................................6-10
6.3.4 Bidirectional Port Considerations ............................................................................6-11
6.3.5 Design Considerations for External Interrupt Inputs ...............................................6-14
6.4 BIDIRECTIONAL PORTS 3 AND 4 (ADDRESS/DATA BUS)...................................... 6-14
6.4.1 Bidirectional Ports 3 and 4 (Address/Data Bus) Operation .....................................6-15
6.4.2 Using Ports 3 and 4 as I/O ......................................................................................6-17
6.4.3 Design Considerations for Ports 3 and 4 ................................................................6-18
6.5 EPORT ........................................................................................................................ 6-18
6.5.1 EPORT Operation ...................................................................................................6-19
6.5.1.1 Reset ..................................................................................................................6-21
6.5.1.2 Output Enable ....................................................................................................6-21
6.5.1.3 Complementary Output Mode ............................................................................6-21
6.5.1.4 Open-drain Output Mode ...................................................................................6-21
6.5.1.5 Input Mode .........................................................................................................6-23
6.5.2 Configuring EPORT Pins ........................................................................................6-24
6.5.2.1 Configuring EPORT Pins for Extended-address Functions ................................6-24
6.5.2.2 Configuring EPORT Pins for I/O ........................................................................6-24
6.5.3 EPORT Considerations ...........................................................................................6-25
6.5.3.1 EPORT Status During Reset, CCB Fetch, Idle, Powerdown, and Hold .............6-25
6.5.3.2 EP_REG Settings for Pins Configured as Extended-address Signals ...............6-25
6.5.3.3 EPORT Status During Instruction Execution ......................................................6-26
6.5.3.4 Design Considerations .......................................................................................6-26
CHAPTER 7
SERIAL I/O (SIO) PORT
7.1 SERIAL I/O (SIO) PORT FUNCTIONAL OVERVIEW ................................................... 7-1
7.2 SERIAL I/O PORT SIGNALS AND REGISTERS .......................................................... 7-2
7.3 SERIAL PORT MODES ................................................................................................. 7-4
7.3.1 Synchronous Mode (Mode 0) ....................................................................................7-4
7.3.2 Asynchronous Modes (Modes 1, 2, and 3) ...............................................................7-5
7.3.2.1 Mode 1 .................................................................................................................7-5
7.3.2.2 Mode 2 .................................................................................................................7-6
7.3.2.3 Mode 3 .................................................................................................................7-7
7.3.2.4 Mode 2 and 3 Timings ..........................................................................................7-7
7.3.2.5 Multiprocessor Communications ..........................................................................7-7
7.4 PROGRAMMING THE SERIAL PORT .......................................................................... 7-8
7.4.1 Configuring the Serial Port Pins ................................................................................7-8
7.4.2 Programming the Control Register ............................................................................7-8
7.4.3 Programming the Baud Rate and Clock Source .......................................................7-8
7.4.4 Enabling the Serial Port Interrupts ..........................................................................7-11
7.4.5 Determining Serial Port Status ................................................................................7-12
7.5 PROGRAMMING EXAMPLE USING AN INTERRUPT-DRIVEN ROUTINE ............... 7-13
CONTENTS
vii