Microchip Technology MCP212X, Руководство пользователя

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MCP212X Developer’s Daughter Board User’s Guide
DS51571B-page 18
©
2006 Microchip Technology Inc.
2.5 MCP212X DEVELOPER’S DAUGHTER BOARD DESCRIPTION
The following sections describe each element of this daughter board in further detail.
2.5.1 Power
The MCP212X Developer’s Daughter Board is powered by a 5V supply. This voltage
supply may be sourced via the PCB headers.
When the device is used in conjunction with the appropriate PICDEM™ Demo Board,
the power is supplied via the connector interface. If the MCP212X Developer’s
Daughter Board is jumpered into an application circuit via the HD1 connector, the
device power supply must be brought over as well.
2.5.2 MCP212X IrDA
®
Standard Encoder/Decoder Device
This demo board highlights the MCP2122 device (U4) and MCP2120 device (U1) to
demonstrate the implementation of an IR port in an embedded system application. The
MCP2120 device handles the encoding/decoding of the UART/IR bit stream.
Further Host Controller interface information is available in the device documentation:
• MCP2122 Data Sheet, “Infrared Encoder/Decoder” (DS21894)
• MCP2120 Data Sheet, “Infrared Encoder/Decoder” (DS21618)
• AN946, “Interfacing the MCP2122 to the Host Controller” (DS00946)
2.5.2.1 MCP2122 OPERATION
The MCP2122 (U4) implements an IrDA standard encoder/decoder. The baud rate is
determined by the frequency of the 16XCLK input.
The key signals for the MCP2122-to-microcontroller (Host UART) interface are shown
in Table 2-4. The key signals for the MCP2122-to-IR transceiver circuit are shown in
Table 2-5.
TABLE 2-4: MCP2122 HOST UART INTERFACE PINS
TABLE 2-5: MCP2122 IR INTERFACE PINS
In addition to the signals described in Table 2-4 and Table 2-5, the MCP2120 RESET
input is connected to the RESET output of the Host Controller.
Pin
Name
Pin
Number
(PDIP)
Pin
Type
Buffer
Type
Description
TX 2 I TTL Asynchronous receive; from Host Controller UART
RX 3 O — Asynchronous transmit; to Host Controller UART
16XCLK 1 I TTL 16 x Clock
Legend: TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels
I = Input O = Output
Pin Name
Pin
Number
(PDIP)
Pin
Type
Buffer
Type
Description
TXIR 2 O — Asynchronous transmit to IrDA
®
standard
transceiver
RXIR 3 I ST Asynchronous receive from infrared transceiver
Legend: A = Analog P = Power
I = Input O= Output