Instruction manual
Table Of Contents
- INTRODUCTION
- GETTING STARTED
- MAKING THE CONNECTIONS
- USING THE PC215E
- STRUCTURE AND ASSIGNMENTS OF THE REGISTERS
- Register Assignments
- Register Groups
- The Register Details
- Programmable Peripheral Interface PPI-X Data Register Port A
- Programmable Peripheral Interface PPI-X Data Register Port B
- Programmable Peripheral Interface PPI-X Data Register Port C
- Programmable Peripheral Interface PPI-X Command Register
- Programmable Peripheral Interface PPI-Y Data Register Port A
- Programmable Peripheral Interface PPI-Y Data Register Port B
- Programmable Peripheral Interface PPI-Y Data Register Port C
- Programmable Peripheral Interface PPI-Y Command Register
- Z1 Counter 0 Data Register
- Z1 Counter 1 Data Register
- Z1 Counter 2 Data Register
- Counter/Timer Z1 Control Register
- Z1 Counter/Timer Status Register
- Z2 Counter 0 Data Register
- Z2 Counter 1 Data Register
- Z2 Counter 2 Data Register
- Counter/Timer Z2 Control Register
- Z2 Counter/Timer Status Register
- Group Z Clock Connection Register
- Group Z Gate Connection Register
- Interrupt Source Selection Register
- Interrupt Status Register
- PROGRAMMING THE PC215E
- Copyright
- Files installed from the Distribution Diskette
- Windows DLL and Examples
- DOS 'C' Library and Examples
- Using the Dynamic Link Library
- Windows and DOS Library Functions
- Initialisation Functions
- Interrupt Control Functions
- Data Buffer Functions
- Timer/Counter Functions
- Differential Counter Functions
- Frequency Generation Functions
- Millisecond Stopwatch Functions
- Frequency Input and Output Functions
- Digitally- and Voltage-Controlled Oscillator Functions
- Digital Input/Output Functions
- Switch Scanner Matrix Functions
- Bi-Directional Data Bus Functions
- PC215E Library Error Codes
- PC215E Interface Guide For LABTECH NOTEBOOK
- Guide to User Programming
- Signal Centre
- CONTENTS
- DECLARATION OF CONFORMITY
PC215E Page 28
5.3.4 Programmable Peripheral Interface PPI-X Command Register
This is the command register for the PPI and can be used to set the operational mode of the
three digital I/O ports or to manipulate the bits of port C.
Register
Offset
Write and/or
Read
Register
Width
Register
Title
Mnemonic
03
16
Write 8 bits
82C55 Programmable Peripheral
Interface PPI-X Command
Register
PPI-X CMD
FUNCTION
Provides a command word to define the operation of the PPI-X ports A, B and C. Any port
programmed as output is initialised to all zeroes when a command word is written. A separate
feature allows any bit of port C to be set or reset using a single instruction.
The programming procedure for the 82C55 is flexible, but the command word must be written
before data bytes are loaded. As the command register and each port have separate addresses
(offsets 0 to 3) and each command word specifies the mode of each port, no other special
instruction sequence is required.
The Three Modes
The register function depends on the setting of bit 7 'Command Select' and the three mode
selections assume that bit 7 is set to '1'. which allows mode configuration.
Mode 0 provides basic input and output operations through each of the ports A, B and C. Output
data bits are latched and input data follows the signals applied to the I/O lines. No handshaking
is needed.
• 16 different configurations in mode 0
• Two 8 bit ports and two 4 bit ports
• Inputs are not latched
• Outputs are latched
Mode 1 provides strobed input and output operations with data transferred through port A or B
and handshaking through port C.
• Two I/O groups (Group A - also known as Group 0 or Group I)
(Group B - also known as Group 1 or Group II)
• Both groups contain an 8 bit port and a 4 bit control/data port
• Both 8 bit data ports can be latched input or latched output