Microchip Technology MCP2200EV-VCP データシート

 2011 Microchip Technology Inc.

DS22228B-page 5

1.3.3

CUSTOM BAUD RATES

Custom baud rates are configured by sending the
SET_LINE_CODING USB

 command, or by using the

DLL. See 

 for more

information.

1.3.4

HARDWARE FLOW CONTROL

Hardware flow control uses the RTS and CTS pins as
a handshake between two devices. The RTS pin of
one device is typically connected to the CTS of the
other device.

RTS is an active low output that notifies the other
device when it is ready to receive data by driving the pin
low. The MCP2200 trip point for de-asserting RTS
(high) is 63 characters. This is one character short of
“buffer full”.
CTS is an active low input that notifies the MCP2200
when it is ready to send data. The MCP2200 will check
CTS just before loading and sending UART data. If the
pin is asserted during a transfer, the transfer will con-
tinue. Refer to 

.

1.3.4.1

Flow Control Disabled

The buffer pointer does not increment (or reset to
zero) if the buffer is full. Therefore, if hardware flow
control is not enabled and an overflow occurs (i.e., 65
unprocessed characters received), the new data
overwrites the last position in the buffer.

The USB controller in the MCP2200 is full-speed USB
2.0 compliant. 
• Composite device (CDC + HID):

- CDC: USB-to-UART communications
- HID: I/O control, EEPROM access and initial 

configuration

• 128 byte buffer to handle data throughput at any 

UART baud rate:
- 64-byte transmit
- 64-byte  receive

• Fully configurable VID and PID assignments, and 

descriptors (stored on-chip)

• Bus powered or self-powered

1.4.1

DESCRIPTORS

During configuration, the supplied PC interface stores
the descriptors in the MCP2200.

1.4.2

SUSPEND AND RESUME

The USB Suspend and Resume signals are supported
for power management of the MCP2200. The device
enters Suspend mode when “suspend signaling” is
detected on the bus.
The MCP2200 exits Suspend mode when any of the
following events occur:
1.

“Resume signaling” is detected or generated

2.

A USB “Reset” signal is detected

3.

A device Reset occurs

The MCP2200 has a built-in, USB 2.0, full-speed
transceiver internally connected to the USB module.
The USB transceiver obtains power from the V

USB

pin,

which is internally connected to the 3.3V regulator. The
best electrical signal quality is obtained when V

USB

 is

locally bypassed with a high quality ceramic capacitor.

1.5.1

INTERNAL PULL-UP RESISTORS

The MCP2200 devices have built-in pull-up resistors
designed to meet the requirements for full-speed USB.

1.5.2

MCP2200 POWER OPTIONS

The following are the main power options for the
MCP2200:
• USB Bus Powered (5V) 
• 3.3V Self Powered

 

Where:

RTS

RTS

CTS

CTS

I am ready
to receive

I’ll transmit
if okay

I am ready
to receive

I’ll transmit
if okay