ft232hq Future Technology Devices International Ltd., ft232hq Datasheet - Page 41

• Manufacturer Part Number: ft232hq
• Description: Ft232h Single Channel Hi- Speed Usb To Multipurpose Uart/fifo Ic
• Manufacturer: Future Technology Devices International Ltd.

4.9.1 Outgoing Fast Serial Data
To send fast serial data out of the FT232H, the external device must drive the FSCLK clock. If the FT232H
has data ready to send, it will drive FSDO output low to indicate the start bit. It will not do this if it is
currently receiving data from the external device. This is illustrated in Figure 4.18
Figure 4.18 Fast Serial Interface Output Data
Notes :-
4.9.2 Incoming Fast Serial Data
An external device is allowed to send data into the FT232H if FSCTS is high. On receipt of a zero START
bit on FSDI, the FT232H will drop FSCTS on the next positive clock edge. The data from bits 0 to 7 are
then clocked in (LSB first). The last bit (DEST) determines where the data will be written to. The data can
be sent to either channel A or to channel B. If DEST= „0‟, the data is sent to channel A, (assuming
channel A is enabled for fast serial mode, otherwise the data is sent to channel B). If DEST= „1‟ the data
is sent to channel B, (assuming channel B is enabled for fast serial mode, otherwise the data will go to
channel A. (Either channel A, channel B or both channels must be enabled as fast serial mode or the
function is disabled). This is illustrated in Figure 4.19
Figure 4.19 Fast Serial Interface Input Data
Notes:-
FSCTS
FSCLK
FSDI
1. The first bit output (Start bit) is always 0.
2. FSDO is always sent LSB first.
3. The last serial bit output is the source bit (SRCE) is always 0.
4. If the target device is unable to accept the data when it detects the START bit, it should stop the
1. The first bit input (Start bit) is always 0.
2. FSDI is always received LSB first.
3. The last received serial bit is the destination bit (DEST) is always 0.
4.
FSCLK
FSDO
FSCLK until it can accept the data.
data bit 0 (D0) and stays low until the chip can accept more data.
The target device should ensure that FSCTS is high before it sends data. FSCTS goes low after
Start
Bit
0
Start
Bit
0
D0
Copyright © 2011 Future Technology Devices International Limited
D0
D1
FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC
D1
D2
D2
Data Bits - LSB first
D3
Data Bits - LSB first
D3
D4
D4
D5
D5
D6
D6
D7
D7
Destination
DEST
Bit
Source
SRCE
Bit
Document No.: FT_000288
Clearance No.: FTDI #199
Datasheet Version 1.0
41