Document No.: FT_000061
FT2232H DUAL HIGH SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 2.09
Clearance No.: FTDI#77
4.6.1 MPSSE Adaptive Clocking
Adaptive clocking is a new MPSSE feature added to the FT2232H MPSSE engine.
The mode is effectively handshaking the CLK signal with a return clock RTCK. This is a technique used by
ARM processors.
The FT2232H will assert the CLK line and wait for the RTCK to be returned from the target device to
GPIOL3 line before changing the TDO (data out line).
TDO
TCK
GPIOL3
RTCK
ARM CPU
FT2232H
Figure 4.8 Adaptive Clocking Interconnect
TDO changes on falling
edge of TCK
TDO
TCK
RTCK
Figure 4.9: Adaptive Clocking waveform.
Adaptive clocking is not enabled by default.
See: AN_108 Command Processor for MPSSE and MCU Host Bus Emulation Modes.
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