2002 Microchip Technology Inc.
Preliminary
DS21655B-page 7
MCP2150
2.0
DEVICE OPERATION
The MCP2150 is a cost effective, low pin count (18-
pin), easy to use device for implementing IrDA stan-
dard wireless connectivity. The MCP2150 provides
support for the IrDA standard protocol “stack” plus bit
encoding/decoding. The Serial interface and IR baud
rates are independantly selectable.
2.1
Power Up
lowed by an Oscillator Start-up Timer (OST) delay
nication with the device may be initiated. This commu-
nication is from both the infrared transceiver’s side as
well as the controller’s UART interface.
2.2
Device Reset
The MCP2150 is forced into the reset state when the
RESET pin is in the low state. Once the RESET pin is
brought to a high state, the Device Reset sequence
occurs. Once the sequence completes, functional
operation begins.
2.3
Clock Source
The MCP2150 requires a clock source to operate. The
frequency of this clock is 11.0592 MHz (electrical spec-
either a crystal/resonator or as an external clock input.
2.3.1
CRYSTAL OSCILLATOR / CERAMIC
RESONATORS
A crystal or ceramic resonator can be connected to the
OSC1 and OSC2 pins to establish oscillation
the use of a parallel cut crystal. Use of a series cut crys-
tal may give a frequency outside of the crystal
manufacturers specifications.
FIGURE 2-1:
CRYSTAL OPERATION
(OR CERAMIC
RESONATOR)
TABLE 2-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
TABLE 2-2:
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
2.3.2
EXTERNAL CLOCK IN
For applications where a clock is already available
elsewhere, users may directly drive the MCP2150 pro-
vided that this external clock source meets the AC/DC
shows how an external clock circuit should be
configured.
FIGURE 2-2:
EXTERNAL CLOCK INPUT
OPERATION
C1 and C2.
Note:
A series resistor may be required for AT
strip cut crystals.
C1
C2
XTAL
OSC2
RS
OSC1
RF
To internal
MCP2150
Note
logic
Freq
OSC1 (C1)
OSC2 (C2)
11.0592 MHz
10 - 22 pF
Higher capacitance increases the stability of the oscil-
lator but also increases the start-up time. These val-
ues are for design guidance only. Since each
resonator has its own characteristics, the user should
consult the resonator manufacturer for appropriate
values of external components.
Freq
OSC1 (C1)
OSC2 (C2)
11.0592 MHz
15 - 30 pF
Higher capacitance increases the stability of the oscil-
lator but also increases the start-up time. These val-
ues are for design guidance only. RS may be required
to avoid overdriving crystals with low drive level spec-
ification.
Since
each
crystal
has
its
own
characteristics, the user should consult the crystal
manufacturer for appropriate values of external
components.
Clock From
external
MCP2150
OSC1
OSC2
Open
system