MCP2120-I/SLG Microchip Technology, MCP2120-I/SLG Datasheet - Page 7

• Manufacturer Part Number: MCP2120-I/SLG
• Description: Infrared encoder/decoder, -40C to +85C, 14-SOIC 150mil, TUBE
• Manufacturer: Microchip Technology

2.5
When the UART receives data to be transmitted, the
data needs to be modulated. This modulated signal
drives the IR transceiver module.
encoding of the modulated signal.
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, then the TXIR pin will output a low level for
7-bit clock cycles, a logic high level for 3-bit clock
cycles, and then the remaining 6-bit clock cycles will be
low. If the value to transmit is a logic high, then the
TXIR pin will output a low level for the entire 16-bit clock
cycles.
FIGURE 2-2:
FIGURE 2-3:
© 2007 Microchip Technology Inc.
BITCLK
(CLK)
BITCLK
RXIR
RX
TX
TXIR
Modulation
Start Bit
16 CLK
Start Bit
16 CLK
Encoding
Decoding
≥ 1.6 µs
0
16 CLK
8 CLK
7 CLK
0
12 Tosc
Figure 2-2
Data bit 0
Data bit 0
13 CLK (or ≤ 50.5 µs typical)
1
16 CLK
shows the
1
Data bit 1
Data bit 1
0
16 CLK
0
Data bit 2
2.6
The modulated signal from the IR transceiver module
needs to be demodulated to form the received data. As
demodulation occurs, the bit value is placed on the RX
pin in UART format.
the modulated signal.
Each bit time is comprised of 16 bit clocks. If the value
to be received is a logic low, then the RXIR pin will be
a low level for the first 3-bit clock cycles, and then the
remaining 13-bit clock cycles will be high. If the value to
be received is a logic high, then the RXIR pin will be a
high level for the entire 16-bit clock cycles. The level on
the RX pin will be in the appropriate state for the entire
16 clock cycles.
Data bit 2
0
16 CLK
Demodulation
0
Data bit ...
Data bit...
1
Figure 2-3
16 CLK
1
MCP2120
shows the decoding of
0
16 CLK
DS21618B-page 7
0