Document No.: FT_000288
FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 1.3
Clearance No.: FTDI #199
3.5.3 FT232H pins used in an FT245 Style Asynchronous FIFO Interface
The FT232H can be configured as a FT245 style asynchronous FIFO interface. When configured in this
mode, the pins used and the descriptions of the signals are shown in Table 3.8. To enter this mode the
external EEPROM must be set to 245 asynchronous FIFO mode. In this mode, data is written or read on
the falling edge of the RD# or WR# signals.
Pin No.
Name
Type
FT245 Configuration Description
13, 14, 15, 16, 17,
18, 19,20
D7 to D0 bidirectional FIFO data. This bus is normally input
unless RD# is low.
ADBUS[7:0]
I/O
When high, do not read data from the FIFO. When low, there is
data available in the FIFO which can be read by driving RD#
low. When RD# goes high again RXF# will always go high and
only become low again if there is another byte to read. During
reset this signal pin is tri-state, but pulled up to VCCIO via an
internal 200kΩ resistor.
21
25
RXF#
TXE#
OUTPUT
OUTPUT
When high, do not write data into the FIFO. When low, data
can be written into the FIFO by strobing WR# high, then low.
During reset this signal pin is tri-state, but pulled up to VCCIO
via an internal 200kΩ resistor.
Enables the current FIFO data byte to be driven onto D0...D7
when RD# goes low. Fetches the next FIFO data byte (if
available) from the receive FIFO buffer when RD# goes high.
26
27
RD#
WR#
INPUT
INPUT
Writes the data byte on the D0...D7 pins into the transmit FIFO
buffer when WR# goes from high to low.
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.
28
SIWU#
INPUT
During normal operation (PWREN# = 0), if this pin is strobed
low any data in the device RX 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 optimize USB transfer
speed for some applications. Tie this pin to VCCIO if not used.
Table 3.8 FT245 Style Asynchronous FIFO Configured Pin Descriptions
For a functional description of this mode, please refer to section 4.5
Copyright © 2011 Future Technology Devices International Limited
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