cs4237b Cirrus Logic, Inc., cs4237b Datasheet - Page 19

• Manufacturer Part Number: cs4237b
• Description: Crystalclear Advanced Audio System With 3d Sound
• Manufacturer: Cirrus Logic, Inc.

The Crystal key places the part in the configura-
tion mode. Once the Crystal key has been
initiated, new PnP resource data can be down-
loaded by a hostload sequence, or an alternate
method of programming the configuration regis-
ters may be used. This alternate method is
referred to as the "SLAM" method. The SLAM
method allows the user to directly access the
configuration registers, configure, and activate
the chip, and then, optionally, disable the PnP
and/or Crystal key feature. The SLAM method
uses commands that are similar to the PnP com-
mands; however, they are different since the user
has direct access to the configuration registers.
To use the SLAM method, see the Bypassing
PnP section.
The following 32 bytes, in hex, are the Crystal
key:
Bypassing Plug and Play
The SLAM method allows the user to bypass the
Plug and Play features and, as an option, allows
the part to act like a non-Plug and Play or legacy
device; however, the SLAM method only sup-
ports one Crystal IC per system. The user
directly programs the resources into the part, and
then optionally disables the PnP and/or the Crys-
tal Key, which forces the part to disregard any
future PnP or Crystal initiation key sequences
(All activated logical devices appear as legacy
devices to PnP). The Crystal and PnP keys can
also be disabled through the E
DS213PP4
96, 35, 9A, CD, E6, F3, 79, BC,
5E, AF, 57, 2B, 15, 8A, C5, E2
F1, F8, 7C, 3E, 9F, 4F, 27, 13,
09, 84, 42, A1, D0, 68, 34, 1A
2
PROM.
To use the SLAM method, the following se-
quence must be followed:
1. Host sends 32-byte Crystal key to I/O
2. Host programs CSN (Card Select Number)
3. Host programs the configuration registers of
4. Repeat #3 for each logical device to be en-
5. Host activates chip by writing a 79h to 279h.
6. (Optional) Host disables PnP Key by writing
0279h, chip enters configuration mode.
by writing a 06h and 00h to I/O 0279h.
each logical device by writing to I/O 0279h.
The following data is the maximum amount
of information per device. All current devices
only need a subset of this data:
abled. (Not all devices need be enabled.)
a 55h to CTRLbase+5. The part will not par-
ticipate in any future PnP cycles. The Crystal
Key can also be disabled by writing a 56h to
CTRLbase+5.
Logical Device ID (15h, xxh)
I/O Port Base Address 0 (47h, xxh, xxh)
I/O Port Base Address 1 (48h, xxh, xxh)
I/O Port Base Address 2 (42h, xxh, xxh)
Interrupt Select 0 (22h, xxh)
Interrupt Select 1 (27h, xxh)
DMA Select 0 (2Ah, xxh)
DMA Select 1 (25h, xxh)
Activate Device (33h, 01h)
xxh is logical device number: 0-5
high byte , low byte
high byte , low byte
high byte , low byte
(33h, 00h deactivates a device)
CS4237B
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