FT4232H QUAD HIGH SPEED USB TO MULTIPURPOSE UART/MPSSE IC
Datasheet
Version 2.4
Document No.: FT_000060 Clearance No.: FTDI#78
3.1.4.3
FT4232H pins used in an MPSSE
The FT4232H channel A and channel B, each have a Multi-Protocol Synchronous Serial Engine (MPSSE).
Each MPSSE can be independently configured to a number of industry standard serial interface protocols
such as JTAG, I2C or SPI, or it can be used to implement a proprietary bus protocol. For example, it is
possible to use one of the FT4232H’s channels (e.g. channel A) to connect to an SRAM configurable FPGA
such as supplied by Altera or Xilinx. The FPGA device would normally be un-configured (i.e. have no
defined function) at power-up. Application software on the PC could use the MPSSE to download
configuration data to the FPGA over USB. This data would define the hardware function on power up. The
other MPSSE channel (e.g. channel B) would be available for another serial interface function while channel
C and channel D can be configured as UART or bit-bang mode. Alternatively each MPSSE can be used to
control a number of GPIO pins. When configured in this mode, the pins used and the descriptions of the
signals are shown in Table 3.7
Channel A
Pin No.
Channel B
Pin No.
Name
Type
MPSSE Configuration Description
Clock Signal Output. For example:
JTAG – TCK, Test interface clock
SPI – SK, Serial Clock
TCK/SK
OUTPUT
16
17
26
27
Serial Data Output. For example:
JTAG – TDI, Test Data Input
SPI – DO, serial data output
TDI/DO
TDO/DI
TMS/CS
OUTPUT
INPUT
Serial Data Input. For example:
JTAG – TDO, Test Data output
SPI – DI, Serial Data Input
18
19
28
29
Output Signal Select. For example:
JTAG – TMS, Test Mode Select
SPI – CS, Serial Chip Select
OUTPUT
GPIOL0
GPIOL1
GPIOL2
GPIOL3
I/O
I/O
I/O
I/O
General Purpose input/output
General Purpose input/output
General Purpose input/output
General Purpose input/output
21
22
23
24
30
32
33
34
Table 3.7 Channel A and Channel B MPSSE Configured Pin Descriptions
For a functional description of this mode, please refer to section 4.4.
When either Channel A or Channel B or both channels are used in MPSSE mode, Channel C and Channel D
can be configured as asynchronous serial interface (RS232/422/485) or Bit-Bang mode or a combination of
both.
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