MCP2200 breakout board
From DP
| Project Summary | |
|---|---|
| Name: | MCP2200 breakout board |
| Buy it: | Get one for $15 at Seeed Studio |
| Price: | $15 |
| Status: | Test production |
| Manufacturing: | Shipping |
| Forum: | MCP2200 breakout board Forum |
Available now for $15 at Seeed Studio.
The MCP2200 is a new USB to serial converter chip from Microchip. This breakout board brings all the pins to bread-board friendly headers.
- USB CDC virtual serial port interface
- Secondary HID configuration interface
- Up to 8 additional IO
- 256bytes user EEPROM
- TX/RX indicator LEDs
- All pins to bread-board friendly header
The MCP2200 is actually just a PIC 18F14K50 programmed with a firmware, but it's slightly less expensive than the PIC alone.
Contents |
Hardware
Click for a full size schematic image. Schematic and PCB were designed with the freeware version of Cadsoft Eagle, download the latest project files from our Google Code project SVN.
MCP2200
The MCP2200 is actually a PIC 18F14K50 with a special firmware put into it. It requires the same sort of support circuit that a PIC does:
- A reset pin is held high for normal operation with a 1K pull-up resistor (R6)
- C1 is a decoupling capacitor (1uF) for the single MCP2200 supply pin
- An internal 3.3volt regulator supplies the USB peripheral, it requires an external 470nF capacitor (C2)
- A 12Mhz crystal(Y1) and two 27pF capacitor (C3,C4) provide the clock
The chip is powered directly from the 5volt USB supply. Ferrite bead (L1) and 10uF capacitor (C5) filter the supply (not shown).
LEDs
| LED | Pin | Indicates |
|---|---|---|
| D1 | GP6 | USB RX |
| D2 | GP7 | USB TX |
| D3 | GP0 | /SUSPEND |
| D4 | GP1 | CONFIG |
Four LEDs (D1-D4) are connected to the MCP2200 status indicator pins, as shown above. Each LED has a 1K current limiting resistor (R1-R4).
PCB
We used the freeware version of Cadsoft Eagle to make the schematic and PCB. Download the latest board files from SVN.
Some parts are little close in places, especially around the crystal. If you've soldered surface mount boards before this shouldn't be a challenge.
We brought the most common UART signals to a secondary header at the edge of the PCB. This makes it easier to use with a breadboard.
Partslist
Click for a full size placement image.
| Part | Quantity | Value | Package |
|---|---|---|---|
| C1 | 1 | 1uF | C805 |
| C2 | 1 | 470nF | C805 |
| C3, C4 | 2 | 27pF | C805 |
| C5 | 1 | 10uF | SMC_A |
| LED1-4 | 4 | LED | LED-805 |
| IC1 | 1 | MCP2200SS (Microchip USB->serial converter) | SSOP20 |
| L1 | 1 | Ferrite bead 800mA+ | FB805 |
| R1-R4, R6 | 5 | 1k | R805 |
| X1 | 1 | USB MINIB SMD | CONN_MINI_USB_B |
| Y1 | 1 | 12Mhz crystal SMD | 4X6 |
The latest sources and distributors are in the master partlist. See something missing? Please let us know.
Drivers
The MCP2200 appears as a USB CDC (virtual serial port) device. Windows already has a driver, but you need to assign it with an .inf file.
The first time you plug-in adapter Windows will prompt for driver. Point windows to the .inf file supplied in the Microchip download.
After the driver is installed you can go to Windows control panel and see the serial port number assigned to the device.
Configuration utility
In addition to the USB serial port interface, the MCP2200 has a second USB HID interface used to set the device configuration.
A utility in the MCP2200 driver download can program a custom USB VID and PID, change the behavior of the indicator LEDs, and modify other configuration options.
Issues with the MCP2200
Windows XP SP3+ required
Windows XP issues: SP3 or later required!
This is a composite USB device (serial port and HID configuration channel). A composite serial device will only work on Windows XP SP3 and higher. The device will connect and the transmit LED will blink (if configured) but no data is actually sent or received. Read more here and here.
RTS/CTS
RTS/CTS are handled locally on the chip!
The CDC serial device specification doesn't include CTS or RTS. The firmware in the MCP2200 handles the RTS and CTS signals internally. This means it probably can't reset your Arduino for programming.
Get one!
You can get one for $15.
Your purchases at Seeed Studio keep the open source project coming, we sincerely appreciate your support!
Resources
- MCP2200 homepage
- Datasheet [PDF!]
- Drivers and configuration utility
- Breakout board forum
- Manufacturing resources
License
- CC-0, reference boards shouldn't be copyrighted!