Hi experts,
    I got a FTDI device module UMFT4222EV-D, my target are using a GPIO pin and a channel SPI with clock running as 40M Hz.
    So, I looked up the data sheet of the module UMFT4222EV and chipset FT4222, and found it supports different maximum clock frequency.

    In the "UMFT4222EV - USB2.0 to QuadSPI/I2C Bridge Development Module Datasheet Version 1.4" from the FTDI website.
   

3 FT4222H Features and Enhancement
...
The max SPI interface operating clock can be set up to 30MHz in master mode and 20MHz in slave mode.
...

    In the "FT4222H USB2.0 TO QUADSPI/I2C BRIDGE IC Datasheet Version 1.5" from the FTDI website.
   

4.1 Key Features
...
The maximum SPI interface operating clock can be set up to 40MHz in master mode and 20MHz in slave mode.
...

    There is 10MHz lost on UMFT4222EV-D device in master mode, what's going on the device? and for my target, which device I can use? Is there a suggestion?
   
Thanks
TonySH

Hi,
  I do connect the GPIOH with the slave device, I use GPIO to listen pull-high signal from the slave when the slave have data to send to the master via SPI.
 
  It works on our windows application used 232H and slave device when they are both power on. but it is a little bit bothered that I need to add time stamp in the test log and find out the first successful transfered message.
 
  I expect that I run my windows application first, and power on the slave device in second action, then the first log message on the application is what I need. so far, I will get the redundant message because of the default state "TriSt-PU" when starting to run the application. On my current test SOP, the default state is the fake signal for my application. How do I bypass this default state?

8. TriSt-PU – Input pulled up, not used

  Is the definition of TriSt-PU as defined above? What is the definition of "used"? I use FT_writeGPIO() to initialize to zero, is it not defined as "used"?

Best Regards
Tony