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AN232R-01 Bit Bang Modes for the FT232R and FT245R

Copyright © 2006 Future Technology Devices International Ltd.

D2XX Function

Description

FT_SetBitMode

Asynchronous Bit Bang mode is enabled using the FT_SetBitMode

command. A value of 0x01 will enable it and a value of 0x00 will reset the

device mode.

FT_SetBaudRate

The rate of data transfer can be controlled by using the FT_SetBaudRate

command. The maximum Baud rate is 3MBaud, but to allow time for the

data to be setup and held around the WR# strobe the Baud rate should be

less than 1MBaud.

The clock for the Asynchronous Bit Bang mode is actually 16 times the

Baud rate. A value of 9600 Baud would transfer the data at (9600x16) =

153600 bytes per second, or 1 every 6.5 mS.

FT_Write

Data can be written to the device in Asynchronous Bit Bang mode using the

FT_Write command. If multiple bytes are written to the device the values

on the pins will change at the rate set by FT_SetBaudRate.

FT_GetBitMode

FT_GetBitMode returns the instantaneous value of the pins. A single byte

will be returned containing the current values of the pins, both those which

are inputs and those which are outputs.

FT_Read

FT_Read will return a buffer of values which have been sampled from the

pins at the rate set by FT_SetBaudRate. If the read buffers have filled, data

willl be lost. Each byte returned contains the values of the pins, both those

which are inputs and those which are outputs.

Full descriptions of these functions are available in the D2XX Programmer's Guide.

Code examples can be downloaded from http://www.ftdichip.com/Projects/CodeExamples.htm.