MCP215X/40EV-DB Microchip Technology, MCP215X/40EV-DB Datasheet - Page 34

• Manufacturer Part Number: MCP215X/40EV-DB
• Description: BOARD DEMO FOR MCP215X/40
• Manufacturer: Microchip Technology

Specifications of MCP215X/40EV-DB

• Main Purpose: Interface, IrDA
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP2150, MCP2155, MCP2140
• Primary Attributes: PICDEM™ Demo Board Interface
• Processor To Be Evaluated: MCP21x
• Interface Type: UART
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

DS51591A-page 30
2.5.3.2
If the MCP2140 is to be used, then the Optical Transceivers’s RXD signal needs to be
conditioned to be used as the input to the MCP2140’s RXPD/RXPDREF signals.
Figure 2-7 shows the circuit that is used to shape the waveform of the optical Trans-
ceiver’s RXD output. This is done to ensure that the RXD pulse width does not exceed
the specifications of the MCP2140 RXPD input (IR131A) (refer to Parameter IR131A
in the MCP2140 Data Sheet, DS21790). The resistor divider R18 and R13 sets the
RXPDREF reference threshold. Transistor Q6 (MMUN2111LT1) has internal resistors.
If you wish to evaluate a simple PNP device, Q6 can be replaced and resistors for R15
and R20 may need to be added. If R20 is added, do not forget to cut the trace that
shorts out the resistor. Modifications to this waveshaping circuit may be required
depending on your operating requirements (voltage, temperature, etc.).
FIGURE 2-7:
2.5.4
To allow easy access to many of the system signals, two headers (HD1 and HD2) are
on one of the edges of the board. This allows the signals from the MCP215X or
MCP2140 to be easily accessed and connected into an existing application for initial
development or proof-of-concept.
FIGURE 2-8:
MCP2140 WAVESHAPING CIRCUITRY
Signal Header
RXPDREF
RXPD
MCP2140 RXPD WAVEFORM SHAPING CIRCUIT
14-PIN SIGNAL INTERFACE HEADER HD1
RXPDREF
RXPD
TP2
TP1
V
DD
R13
10 k
R19
10 k
Q6
V
R16
4.7 k
HD1
DD
R14
100
1
HD2
R15
OPT
R20
OPT
MMUN2111LT1
47 pF
C14
© 2006 Microchip Technology Inc.
RXD
(From Optical
Transceiver)