FT2232C Dual USB UART / FIFO I.C.
9.0 Signal Descriptions By IO Mode and Interface Channel Configurations
9.1 232 UART Interface Mode Signal Descriptions and Interface Configurations
When either Channel A or Channel B are in 232 UART mode the IO signal lines are configured as follows:-
Pin#
Signal
Type
Description
Channel A Channel B
24
23
22
21
20
19
17
16
40
39
38
37
36
35
33
32
TXD
OUTPUT Transmit Asynchronous Data Output
INPUT Receive Asynchronous Data Input **Note 16
OUTPUT Request To Send Control Output / Handshake signal
INPUT Clear To Send Control Input / Handshake signal **Note 16
OUTPUT Data Terminal Ready Control Output / Handshake signal
RXD
RTS#
CTS#
DTR#
DSR#
DCD#
RI#
INPUT
INPUT
INPUT
Data Set Ready Control Input / Handshake signal **Note 16
Data Carrier Detect Control Input **Note 16
Ring Indicator Control Input. When the Remote Wake up option
is enabled in the EEPROM, taking RI# low can be used to
resume the PC USB Host controller from suspend. **Note 16
15
13
30
29
TXDEN OUTPUT Enable Transmit Data for RS485
SLEEP# OUTPUT Goes low during USB Suspend Mode. Typically used to power-
down an external TTL to RS232 level converter I.C. in USB to
RS232 converter designs.
12
11
10
28
27
26
RXLED# O.C.
TXLED# O.C
LED Drive - Pulses Low when Transmitting Data via USB.
LED Drive - Pulses Low when Receiving Data via USB.
SI/WU
INPUT
The Send Immediate / WakeUp signal combines two functions
on a single pin. If USB is in suspend mode (PWREN# = 1) and
remote wakeup is enabled in the EEPROM , strobing this pin
low will cause the device to request a resume on the USB Bus.
Normally, this can be used to wake up the Host PC.
During normal operation (PWREN# = 0), if this pin is strobed low
any data in the device TX buffer will be sent out over USB on the
next Bulk-IN request from the drivers regardless of the pending
packet size. This can be used to optimise USB transfer speed for
some applications. Tie this pin to VCCIO if not used.
**Note 16 : These pins are pulled to up VCCIO via internal 200K resistors during Reset and USB Suspend mode.
These can be programmed to gently pull low during USB suspend ( PWREN# = “1” ) by setting this option in the
EEPROM.
DS2232C Version 1.2
© Future Technology Devices International Ltd. 2004
Page 28 of 54
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