OVERVIEW
The CS8130 is an infrared transceiver I.C. The
receive channel includes on-chip high gain PIN
diode amplifier, IrDA, HP-SIR, 500 kHz Ampli-
tude Shift Keying (ASK) & TV remote
compatible decoder, and data pulse stretcher. The
transmit path includes IrDA, HPSIR, 500 kHz
ASK & TV remote compatible encoder, and
LED drivers. The computer data port is standard
UART TxD and RxD compatible, and operates
from 1200 to 115200 baud. An on-chip baud rate
generator is provided.
External PIN diode and transmit LED(s) are re-
quired. A control mode is provided to allow easy
UART programming of different modes.
The CS8130 operates from power supplies of
+2.7 V to +5.5 V. The device is supplied in a 20-
pin SSOP package
FUNCTIONAL DESCRIPTION
The following pages describe the detailed opera-
tion of the CS8130.
IR Data Formats
The CS8130 supports three infrared data trans-
mission formats: IrDA/HPSIR, 500kHz ASK and
38kHz ASK (TV Remote). There is also a direct
access mode, which bypasses the CS8130 en-
coder and decoders, and gives direct access to
the IR raw data. This mode is for situations
where the encoding and/or decoding is done ex-
ternally.
Modes may be set independently for transmit
and receive, although this would be unusual.
Mode 1 IrDA/HP-SIR
The CS8130 is designed to allow easy realiza-
tion of an IrDA compatible IR port (see IrDA
Serial Infrared (SIR) Physical Layer Link Speci-
fication, Version 1.0, April 27 1994). Figure 2
shows the format of Mode 1. A pulse of IR en-
ergy indicates a logic ’0’. No IR indicates a
logic ’1’. The pulse can be from 3/16 of a bit
cell time at 115200 (~1.6 µs), to 3/16 of a bit
cell time at 2400 bps (~78 µs). The width of the
pulse may be fixed at 1.6µs for all baud rates, or
may scale with the baud rate. The initial baud
rate for IrDA is 9600 bps, with a negotiated baud
rate possibility of 2400 to 115200 bps.
Mode 2 500 kHz ASK
Figure 3 shows the infrared data format for
Mode 2. This is a Carrier Wave (CW) type sys-
tem, where the presence of a 500kHz carrier is
treated as a ’0’, and absence of a carrier is
treated as a ’1’. Normally used baud rates are
9600 bps, 19.2 kbps and 38.4 kbps.
Mode 3 38 kHz ASK (TV remote mode)
Figure 4 shows the infrared data format for
Mode 3, the TV remote control mode. This is
similar to Mode 2, except that the modulation
frequency is ~38kHz. The IR bit rate is approxi-
mately 2400 bps. Both modulation frequency
and bit rate vary significantly for different manu-
facturer and model remote controls.
Mode 4 Direct Access Mode
In Mode 4, the IR transmission tracks directly
what is present on the TXD pin. A logic ’1’
means that the LED is off, a logic ’0’ means that
the LED is on. Care must be taken to ensure that
the LED is not ’on’ continuously, otherwise the
LED may be damaged.
In Mode 4, received IR is compared against the
programmed threshold. The resulting logic out-
put is routed directly to the RXD pin. A logic ’1’
means no IR is detected, a logic ’0’ means IR is
being detected. If a IR carrier is being received,
CS8130
6 DS134PP2
