UM232H 查看數據表（PDF） - Future Technology
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UM232H Datasheet PDF : 25 Pages
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Document Reference No.: FT_000367
UM232H Single Channel USB Hi-Speed FT232H Development Module
Datasheet Version 1.2
Clearance No.: FTDI# 198
4.3 ACBUS Signal Options
The table below describes the EEPROM options which can be configured on the ACBUS I/O pins using the
software utility FT_PROG (which can be downloaded from the FTDI utilities page) The default EEPROM
configuration is described in section 9.
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 one bit time after the last 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#
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.
RXLED#
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#
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
LED drive – pulses low when transmitting or receiving data
from or to the external device. For more details, refer to
the FT232H datasheet on the FTDI website.
SLEEP#
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
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
30MHz Clock output.
**CLK15
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
15MHz Clock output.
**CLK7.5
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
7.5MHz Clock output.
TriSt-PU
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
Input Pull Up
DRIVE 1
ACBUS0, ACBUS5, ACBUS6,ACBUS8,
ACBUS9
Output High
DRIVE 0
ACBUS0, ACBUS1, ACBUS2, ACBUS3,
ACBUS4, ACBUS5, ACBUS6, ACBUS8,
ACBUS9
Output Low
I/O mode
ACBUS5, ACBUS6,ACBUS8, ACBUS9
Table 4.4 : ACBUS Signal Option
ACBUS BitBang
* A 10kΩ resistor pull up is also recommended.
**When in USB suspend mode, the output clocks are also suspended.
11
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