SCD1283 INTEL [Intel Corporation], SCD1283 Datasheet - Page 19

• Manufacturer Part Number: SCD1283
• Description: IEEE 1284-Compatible Parallel Interface
• Manufacturer: INTEL [Intel Corporation]

4.0
4.1
Datasheet
AER
GFRCR
GPDIR
GPIO
PIR
PPR
SVRR
Name
Table 1. Global Registers
Note: AER must be set to ‘00h’ and must not be changed (except to access RCR), or access to many
Hex
4F
71
7E
68
70
61
67
Register Summary
Local CPU communication with the CD1283 occurs through a register set. Within this register set,
there are four types of registers:
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).
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
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.
Register Summary Tables
•
•
•
•
DMAREQ
PPIreq
Data 7
Global, common to all functions of the device
Parallel pipeline
Parallel port
Service-acknowledge accessible
Bit 7
Dir 7
Poll
Chapter 7.0
Data 6
PPort
Bit 6
Dir 6
Poll
n/u
The address offset defined is the binary value that should be applied to the
Pipeline
Data 5
Bit 5
Dir 5
Poll
n/u
Firmware Revision Code
Data 4
Bit 4
Dir 4
IEEE 1284-Compatible Parallel Interface — CD1283
Poll
n/u
0
Binary Value
Data 3
Bit 3
Dir 3
SRP
Poll
0
Data 2
Bit 2
Dir 2
n/u
0
0
Data 1
Bit 1
Dir 1
n/u
0
0
Data 0
Bit 0
Dir 0
n/u
0
0
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