FT232H datasheet(13/65 Pages) FTDI

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Document No.: FT_000288

FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC

Datasheet Version 1.81

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#

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. See Section 4.11 for more

details.

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

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.

FT232H Datasheet(PDF) 13 Page - Future Technology Devices International Ltd.

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