FT2232H 参数 Datasheet PDF下载

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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