MCP2140 Microchip Technology, Inc., MCP2140 Datasheet - Page 11

• Manufacturer Part Number: MCP2140
• Description: The MCP2140 Embeds Irda Protocol Handling And Bit Encoding/decoding, And Provides The Lowest Cost, Lowest Power Consumption Solution For Adding Irda Connectivity to Embedded Systems
• Manufacturer: Microchip Technology, Inc.

2.5
The encoder converts the UART format data into the
IrDA Standard format data and the decoder converts
IrDA Standard format data into UART format data.
2.5.1
The data that the MCP2140 UART received (on the TX
pin) that needs to be transmitted (on the TXIR pin) will
need to be modulated. This modulated signal drives the
IR transceiver module.
of the modulated signal.
FIGURE 2-5:
2003 Microchip Technology Inc.
Note:
BITCLK
TX Bit
Value
TXIR
Encoder/Decoder
The signal on the TXIR pin does not actu-
ally line up in time with the bit value that
was transmitted on the TX pin, as shown in
Figure
represent the value to be transmitted on
the TXIR pin.
ENCODER (MODULATION)
2-5. The TX bit value is shown to
Start Bit
16 CLK
ENCODING
Figure 2-5
0
7 CLK
24 Tosc
shows the encoding
Data bit 0
1
Data bit 1
Preliminary
0
Each bit time is comprised of 16-bit clocks. If the value
to be transmitted (as determined by the TX pin) is a
logic-low, the TXIR pin will output a low level for 7-bit
clock cycles, a logic high level for 3-bit clock cycles or
a minimum of 1.6 µsec (see
remaining 6-bit clock cycles will be low. If the value to
transmit is a logic-high, the TXIR pin will output a low
level for the entire 16-bit clock cycles.
Data bit 2
0
Data bit ...
1
MCP2140
Parameter
0
DS21790A-page 11
IR121). The