CS4237B Datasheet, PDF (13/114 Pages) Cirrus Logic – CrystalClear Advanced Audio System with 3D Sound

PnP ISA Bus
Interface
CS4237B
Logical Device 0 Logical Device 1 Logical Device 2 Logical Device 3 Logical Device 4 Logical Device 5
WSS Codec:
I/O: WSSbase
2 DMA Chan.
1 Interrupt
Game Port:
I/O: GAMEbase
Control:
I/O: CTRLbase
[1 Interrupt]
MPU-401:
I/O: MPUbase
1 Interrupt
Synthesis:
I/O: SYNbase
[1 Interrupt]
Figure 1. Logical Devices
CDROM:
I/O:
CDbase
ACDbase
[1 Interrupt]
[1 DMA Chan.]
Modem:
I/O: COMbase
[1 Interrupt]
SBPro:
I/O: SBbase
(DMA shared)
(Interrupt shared)
Logical Device 5 supports a modem connected
to the peripheral port. This interface, on the ex-
ternal peripheral port, supports modems with 2
to 256 I/O locations (only SA2-SA0 are buffered
through the part) and supports a base address
and an interrupt. Although this logical device is
listed as a modem, any external device that fits
within the resources listed above may be substi-
tuted.
ISA Bus Interface
The 8-bit parallel I/O and 8-bit parallel DMA
ports provide an interface which is compatible
with the Industry Standard Architecture (ISA)
bus. The ISA Interface enables the host to com-
municate with the various functional blocks
within the part via two types of accesses: Pro-
grammed I/O (PIO) access, and DMA access.
A number of configuration registers must be pro-
grammed prior to any accesses by the host
computer. The configuration registers are pro-
grammed via a Plug-and-Play configuration
sequence or via configuration software provided
by Crystal Semiconductor.
I/O CYCLES
Every device that is enabled, requires I/O space.
An I/O cycle begins when the part decodes a
valid address on the bus while the DMA ac-
knowledge signals are inactive and AEN is low.
The IOR and IOW signals determine the direc-
tion of the data transfer. For read cycles, the part
will drive data on the SD<7:0> lines while the
host asserts the IOR strobe. Write cycles require
the host to assert data on the SD<7:0> lines and
strobe the IOW signal. Data is latched on the ris-
ing edge of the IOW strobe.
DS213PP4
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