Chapter 15
provides access to the pins most often used by microcontroller serial interfaces:
data (TX, RX) and flow control (RTS#, CTS#) plus power and ground (VCC,
and GND.
DLP Design (www.dlpdesign.com) offers modules that add PIC microcontrol-
lers, sensors, and other useful components interfaced to FTDI’s controllers./ ##
Unlike other USB controllers, the FT232R and FT245R aren’t designed as gen-
eral-purpose devices that can be programmed to use any host driver. Instead,
the devices are intended for use with drivers provided by FTDI.$ 8
Using the driver provided by FTDI, applications can access a chip as a virtual
COM port or via a vendor-specific API.
In most cases, using an FT232R to convert an RS-232 device to USB requires
no changes to application software. Applications can continue to access the
device as a COM port. An FT245R functions as a virtual COM Port that trans-
fers parallel data.
For applications that don’t want to use COM-port functions, the driver’s D2XX
DLL defines a vendor-specific API. Both the FT232R and FT245R can use this
API to access the devices. FTDI provides INF files that enable Windows to
match the driver to a device.
: " 3
$
Both controllers contain on-chip EEPROM that can store vendor-specific val-
ues for items such as a Vendor ID, Product ID, serial-number string, other
descriptive strings, and values that specify whether the device is bus- or
self-powered. If there is no EEPROM data for an item, the controller uses a
default value. FTDI provides a utility that programs the information into the
EEPROM. Older versions of the controllers interface to external EEPROMs.
By default, the chips use FTDIs’ Vendor ID and Product ID. On request,
FTDI will grant the right for your device to use their Vendor ID with a Product
ID that FTDI assigns to you. Of course you can use your own Vendor ID and
Product ID if you wish.