CS5535 datasheet(131/555 Pages) NSC

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UART/IR Controller Functional Description (Continued)

4.11.3 Dongle Interface

The dongle interface on the CS5535 is not a fully hardware

compatible interface. The real dongle interface requires six

external interface signals and the CS5535 only supports

three. With only three signals, the dongle interface sup-

ports a subset of the real dongle interface through virtual-

ization.

4.11.3.1 Real Dongle

The real dongle interface uses six multiplexed pins for don-

gle identification, data transfer, and transceiver configura-

tion. Figure 4-35 illustrates the real dongle interface and

Table 4-20 provides the interface signals and their descrip-

tions.

Only three signals (IRTX, IRRX, and ID0/IRSL0/IRRX2) are

used for the IR interface. It has three phases:

Phase 1:

Change the ID0-ID3 bits to input mode, and read the

status to complete primary identification of the dongle.

Phase 2:

Change ID1 and ID2 as output and read the status of

ID0 and ID3 to complete the secondary dongle identifi-

cation phase. This phase provides information about

the connected dongle.

Phase 3:

Configure mode: Change IRSL[2:0] as an output and

configure the transceiver for the required mode. If two

infrared inputs are required, change IRSL0 to an input

to give the second receiver channel IRRX2. The IRSL2

and IRSL1 are configured as outputs to keep the

transceiver in the required mode.

Figure 4-35. Real Dongle Interface

Table 4-20. Real Dongle Interface Signals

Signal Name

Type

Description

IRTX

Infrared transmit data

IRRX

Infrared receive data

ID0/IRSL0/IRRX2

I/O

Identification signal 0

Infrared mode select 0

Infrared receive data for

transceivers with two RX

channels

ID1/IRSL1

I/O

Identification signal 1

Infrared mode select 1

ID2/IRSL2

I/O

Identification signal 2

Infrared mode select 2

ID3

I/O

Identification signal 2

Shielded

Cable

IrDa-Data Transceiver with Receive Channels

RX-A

RX-B

Controller

Transceiver Select Logic

Resistance

Pull-up

VCC

IRTX

IRRXI

ID0/IRSL0/IRRX2

ID1/IRSL1

ID2/IRSL2

ID3

ASIC Boundary

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