Document No.: FT_000288
FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 1.8
Clearance No.: FTDI #199
4.9 Fast Serial Interface Mode Description
Fast Serial Interface Mode provides a method of communicating with an external device over USB using 4
wires that can have opto-isolators in their path, thus providing galvanic isolation between systems. Fast
serial mode is enabled by setting the appropriate bits in the external EEPROM. The fast serial mode can
be held in reset by setting a bit value of 0x10 using the FT_SetBitMode D2xx driver command. While this
bit is set the device is held reset – data can be sent to the device, but it will not be sent out by the device
until the device is enabled again. This is done by sending a bit value of 0x00 using the Set Bit Mode
command.
When the FT232H is configured in Fast Serial Interface mode the IO timing of the signals used are shown
in Figure 4.17 and the timings are shown in Table 4.5 Fast Serial Interface Signal Timings.
Figure 4.17 Fast Serial Interface Signal Waveforms
Name
t1
Minimum Typical
Maximu Units
Description
5
5
ns
ns
ns
ns
ns
ns
ns
FSDO/FSCTS hold time
FSDO/FSCTS setup time
FSDI hold time
FSDI Setup Time
FSCLK low
t2
t3
5
t4
10
10
10
20
t5
t6
FSCLK high
t7
FSCLK Period
Table 4.5 Fast Serial Interface Signal Timings
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