CD1284 —
IEEE 1284-Compatible Parallel Interface Controller
4
Datasheet
5.10
5.11
Serial Diagnostic Facilities
—
Loopback.............................................................73
Parallel Port FIFO and Data Pipeline Overview..................................................73
5.11.1 IEEE STD 1284 Protocols......................................................................73
5.11.2 Bus Interface..........................................................................................74
5.11.3 Parallel Port FIFO ..................................................................................74
5.11.4 Receive Direction...................................................................................75
5.11.5 Receiving Compressed Data..................................................................75
5.11.6 Stale Data (Stale, OneChar, and Timeout Status Bits)..........................76
5.11.7 Transmit Direction..................................................................................76
CD1284 Parallel Port Overview ..........................................................................77
5.12.1 Terminology ...........................................................................................77
5.12.2 Signal Names.........................................................................................77
5.12.3 State Machine ........................................................................................78
5.12.4 Configuration..........................................................................................78
5.12.5 Interrupts................................................................................................79
5.12.6 Manual Mode .........................................................................................79
5.12.7 Control Signals.......................................................................................79
5.12.8 Parallel Port Interface to the FIFO .........................................................80
5.12.9 1284 Negotiations ..................................................................................80
5.12.10 Data Transfers .......................................................................................81
5.12.11 Compatible Mode Status........................................................................81
1284 Parallel Protocol Support ...........................................................................82
5.13.1 Compatibility Mode.................................................................................82
5.13.2 Reverse-Nibble and Reverse-Byte Modes.............................................82
5.13.3 ID Request .............................................................................................82
5.13.4 ECP Mode..............................................................................................82
5.13.5 EPP Mode..............................................................................................83
Protocol Timing ...................................................................................................83
General-Purpose I/O Port ...................................................................................83
Parallel Port Interface..........................................................................................84
Hardware Configurations ....................................................................................86
5.17.1 Interfacing to an Intel
Microprocessor-Based System...........................86
5.17.2 Interfacing to a Motorola
Microprocessor-Based System......................86
5.17.3 Interfacing to a National Semiconductor
Microprocessor-Based System86
Programming
.............................................................................................................90
6.1
Overview .............................................................................................................90
6.2
Initialization .........................................................................................................90
6.2.1
Device Reset..........................................................................................90
6.2.2
Global Function Initialization ..................................................................93
6.2.3
Serial Channel Initialization....................................................................93
6.3
Serial Poll Mode Examples.................................................................................94
6.3.1
Polling Routine Examples ......................................................................94
6.4
Hardware-Activated Service Examples...............................................................97
6.4.1
Serial Receive Service...........................................................................97
6.4.2
Serial Transmit Service..........................................................................98
6.4.3
Modem Service ......................................................................................99
6.5
Parallel Channel Service Routines......................................................................99
6.5.1
Software-Activated Service Examples (Poll)........................................100
5.12
5.13
5.14
5.15
5.16
5.17
6.0