MCP2140_03 Datasheet, PDF (8/58 Pages) Microchip Technology – IrDA® Standard Protocol Stack Controller With Fixed 9600 Baud Communication Rate

MCP2140
2.3.1.2 External Clock
For applications where a clock is already available
elsewhere, users may directly drive the MCP2140 pro-
vided that this external clock source meets the AC/DC
timing requirements listed in Section 4.3, “Timing Dia-
grams and Specifications”. Figure 2-2 shows how an
external clock circuit should be configured.
FIGURE 2-2:
Clock From
external
system
Open
EXTERNAL CLOCK
OSC1 ^MCP2140
OSC2
2.3.2 BIT CLOCK
The device crystal is used to derive the communication
bit clock (BITCLK). There are 16 BITCLKs for each bit
time. The BITCLKs are used for the generation of the
start bit and the eight data bits. The stop bit uses the
BITCLK when the data is transmitted (not for
reception).
This clock is a fixed-frequency and has minimal
variation in frequency (specified by the crystal
manufacturer).
DS21790A-page 8
Preliminary
 2003 Microchip Technology Inc.