User Manual EPT USB To Serial 1 Meter Cable
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EPT 232R-US-R1 Key Features
This section summarises the key features and enhancements of the FT232R IC device which is
used on the EPT 232R-US-R1 USB to RS232 converter cable. For further details, consult the
FT232R datasheet, which is available from the FTDI website.
2.1
Pre-programmed EEPROM
The FT232R is supplied with its internal EEPROM pre-programmed with a serial number which
is unique to each individual device. This, in most cases, will remove the need to program the
device EEPROM.
2.2
Lower Operating and Suspend Current
The device operating supply current has been further reduced to 15mA,
and the suspend current has been reduced to around 70μA. This allows greater margin for
peripheral designs to meet the USB suspend current limit of 500μA.
2.3
Low USB Bandwidth Consumption
The operation of the USB interface to the FT232R has been designed to use as little as possible
of the total USB bandwidth available from the USB host controller.
2.4
Improved EMI Performance
The reduced operating current and improved on-chip VCC decoupling significantly improves the
ease of PCB design requirements in order to meet FCC, CE and other EMI related specifications.
2.5
Programmable Receive Buffer Timeout
The receive buffer timeout is used to flush remaining data from the
receive buffer. This time defaults to 16ms, but is programmable over USB in 1ms increments
from 1ms to 255ms, thus allowing the device to be optimised for protocols that require fast
response times from short data packets.
2.6
Baud Rates
The FT232R supports all standard baud rates and non-standard baud rates from 300 Baud up to 3
Mbaud. Achievable non-standard baud rates are calculated as follows –
Baud Rate = 3000000 / (n + x)
where n can be any integer between 2 and 16,384 ( = 214 ) and x can be a sub-integer of the
value 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, or 0.875. When n = 1, x = 0, i.e. baud rate divisors
with values between 1 and 2 are not possible.
This gives achievable baud rates in the range 183.1 baud to 3,000,000 baud. When a non-
standard baud rate is required simply pass the required baud rate value to the driver as normal,
