CD1283 Datasheet, PDF (19/94 Pages) Intel Corporation – IEEE 1284-Compatible Parallel Interface

IEEE 1284-Compatible Parallel Interface — CD1283
4.0
Register Summary
Local CPU communication with the CD1283 occurs through a register set. Within this register set,
there are four types of registers:
• Global, common to all functions of the device
• Parallel pipeline
• Parallel port
• Service-acknowledge accessible
Global registers are always available to the CPU and their addresses are not affected by the
contents of the AER (this register is provided to maintain compatibility with the CD1284).
Note: AER must be set to ‘00h’ and must not be changed (except to access RCR), or access to many
registers will not work properly!
The following tables define the register names, read and write access modes, internal address
offsets, and bit definitions. A detailed description of each register, its contents and functions can be
found in Chapter 7.0 The address offset defined is the binary value that should be applied to the
address inputs (A[6:0]) during I/O cycles.
Note that the addresses are shown relative to the CD1283 definition of address lines. In 16- and 32-
bit systems, it is a common practice to connect 8-bit peripherals to only one byte lane. Thus, in 16-
bit systems, the CD1283 appears at every other address (for example, the CD1283 A[0] input is
connected to CPU A[1]). In 32-bit systems, the CD1283 appears at every fourth address (CD1283
A[0] is connected to CPU A[2]). In either of these cases, the address used by the programmer will
be different than what is shown in the tables. For instance, in a 16-bit Motorola^ 68000-based
system, the CD1283 is placed on data lines D[7:0], which are at odd addresses in the Motorola
scheme of addressing. The CD1283 A[0] input is connected with A[1] of the 68000, A[1] with
A[2], and so on. Thus, the CD1283 address 0x40 becomes 0x81 to the programmer. It is left-
shifted one bit and A[0] must be ‘1’ for low-byte (D[7:0]) accesses.
4.1
Register Summary Tables
Table 1. Global Registers
Name Hex
Bit 7
Bit 6
AER
GFRCR
GPDIR
GPIO
PIR
PPR
SVRR
68
Poll
Poll
4F
71
Dir 7
Dir 6
70
Data 7
Data 6
61
PPIreq
PPort
7E
67 DMAREQ
n/u
Bit 5
Bit 4
Bit 3
Bit 2
Poll
Poll
Poll
Firmware Revision Code
Dir 5
Dir 4
Dir 3
Data 5
Data 4
Data 3
Pipeline
0
0
Binary Value
n/u
n/u
SRP
0
Dir 2
Data 2
0
n/u
Bit 1
0
Dir 1
Data 1
0
n/u
Bit 0
0
Dir 0
Data 0
0
n/u
Page
53
53
54
54
54
55
55
Datasheet
19