Document No.: FT_000288
FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 1.8
Clearance No.: FTDI #199
3.4 ACBUS Signal Option
If the external EEPROM is fitted, the following options can be configured on the CBUS I/O pins using the
software utility FT_PROG which can be downloaded from the FTDI utilities page. CBUS signal options are
common to both package versions of the FT232H. The default configuration is described in section 7.
ACBUS Signal
Option
Available On ACBUS Pin
Description
TXDEN
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
TXDEN = (TTL level). Used with RS485 level converters to
enable the line driver during data transmit. TXDEN is
active from one bit time before the start bit is transmitted
on TXD until the end of the stop bit.
*PWREN#
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
Output is low after the device has been configured by
USB, then high during USB suspend mode. This output can
be used to control power to external logic P-Channel logic
level MOSFET switch. Enable the interface pull-down
option when using the PWREN# in this way.*
TXLED#
RXLED#
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
TXLED = Transmit signalling output. Pulses low when
transmitting data (TXD) to the external device. This can
be connected to an LED.
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
RXLED = Receive signalling output. Pulses low when
receiving data (RXD) from the external device. This can be
connected to an LED.
TX&RXLED#
SLEEP#
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
LED drive – pulses low when transmitting or receiving data
from or to the external device. See Section 4.11 for more
details.
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
Goes low during USB suspend mode. Typically used to
power down an external TTL to RS232 level converter IC
in USB to RS232 converter designs.
**CLK30
**CLK15
**CLK7.5
TriSt-PU
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
30MHz Clock output.
15MHz Clock output.
7.5MHz Clock output.
Input Pull Up
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
DRIVE 1
DRIVE 0
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
Output High
Output Low
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
I/O mode
ACBUS5, ACBUS6,ACBUS8, ACBUS9
ACBUS BitBang
Table 3.5 ACBUS Configuration Control
* Must be used with a 10kΩ resistor pull up.
**When in USB suspend mode the outputs clocks are also suspended.
Copyright © 2012 Future Technology Devices International Limited
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ETC [ ETC ]
