CS5535 datasheet(132/555 Pages) NSC

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Revision 0.8

UART/IR Controller Functional Description (Continued)

4.11.3.2 Virtual Dongle

The virtual dongle interface is used due to the unavailability

of pins for dongle identification and configuration (see Fig-

ure 4-36).

The virtual dongle interface is a method used to run legacy

software on the UART/IR Controller. The virtual dongle

interface uses dedicated UART/IR MSRs. (See Section

5.12.1 "UART/IR Controller Specific MSRs" on page 363

for complete register and bit formats.) The virtual dongle

imitates the real dongle as far as legacy software is con-

cerned, and there are no plug-and-play requirements for IR

transceivers.

• The software inputs the dongle's ID to the ID[0:3] bits of

MSR_UART[x]_MOD (UART1 MSR 51400038h and

UART2 MSR 5140003Ch) as the primary ID encoding.

• For dongles that use a non-serial transceiver, it identifies

the Consumer IR capabilities. The software should

switch ID1 and ID2 to output mode (so they become

IRSL1 and IRSL2), IRSL1 and IRSL2 will or will not

behave differently (i.e., INV [invert] or NCH [no change])

from the previous step and the software should respond

by driving the appropriate level on ID0 and ID3 in the

MSR_UART[x]_DONG register.

The operational mode of an infrared dongle that uses a

non_serial transceiver is selected by the driving the

IRSL[2:0] signals.

Features

• Uses only three pins to connect to IR transceiver.

• Fully supports legacy software written for real dongle,

with some manual intervention.

• All real dongle modes can be supported by changing the

MSR.

Limitations

• No Plug-and-Play features available.

• IRSL1 and IRSL2 pins need to be tied in the IR trans-

ceiver for the required mode.

• MSR contents must be changed when changing the

transceiver mode. If BIOS is used to change the MSR

contents, it must be a factory setting.

• If the legacy software supports IR transceiver configura-

tion, the contents of IRSL[2:0] are to be read from the

MSR and the required bit tieing needs to be done in the

transceiver board.

Figure 4-36. Virtual Dongle Interface

Mux

IR Controller

ID1

ID2

ID0

ID3

UART/IR Controller

MSR_UART[x]_MOD

MSR_UART[x]_DONG

IRSL0

IRSL1

IRSL2

IRTX

IRRX1

ASIC Boundary

IR Transceiver

Tie IRSL1

and IRSL2

IRSL1

IRSL2

ID1

ID2

ID0

ID3

ID0_SEC ID3_SEC

CS5535 Datasheet(PDF) 132 Page - National Semiconductor (TI)

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