FT4232H QUAD HIGH SPEED USB TO MULTIPURPOSE UART/MPSSE IC
Datasheet
Version 2.4
Document No.: FT_000060 Clearance No.: FTDI#78
6.4 4 Channel Transmit and Receiver LED Indication Example
The following example illustrates how a 74HCT595 can be used to decode the EEDATA data to indicate Tx
and Rx on each of the channels. The associated LED will light when the Channel is transmitting or receiving
data.
VIO= VCCIO
PWREN#
EECS
EECLK
EEDATA
SN74HC595D
Figure 6.6 Using 74HC595 to Indicate Tx and Rx Data
In this configuration, the LEDs will flash when the EEPROM is accessed e.g. during enumeration.
Under normal operation, the EECS is held low to disable access to the EEPROM. In this special case, the
EECLK (frequency = 1.56µS) will clock the EEDATA into the 74HC595 shift register (with EECS low,
therefore EEPROM ignores the EEDATA). Then EECS will pulse high. The rising edge of the EECS latches the
data into a storage register of the 74HC595 which drives the LEDs.
Please refer to the 74HC595 datasheet for further explanation.
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