Re: libftdi@xxxxxxxxxxxxxxxxxxxxxxx is a subscribers only list

[Vladimir Yakovlev <nagos@xxxxxxxx>]

2011/3/16 Petr Jakeš <petr.jakes@xxxxxx>

I used FT2232D for SPI.  Even with all the extra overhead I've described previously, 200kbps would not be difficult.

I use FT2232H to boot Altera FPGA (SPI), it took ~50ms to transfer 160kbyte firmware, this give average speed 23Mbit/s. I use maximum clock (divider = 0, x5 enabled).

Thanks to all for your replies.

To be more specific we are thinking about to drive the chain of Starchips technology 16-bit Constant-Current LED Drivers using FTDI.

To achive this goal we need:

SPI (MOSI, MISO, CLK)

1x PWM (5kHz to 10 kHz)

1x Output pin (output signal frequency max. 50 Hz)

Do you think this is doable using the FTDI chip? If yes, any hints and/or examples are highly appreciated.

SPI - easy, look at code of flashrom project http://flashrom.org/trac/flashrom/browser/trunk/ft2232_spi.c
PWM - i doubt you can do it. When using bitbang mode, data rate is unstable,  CPU need constantly send data (every pwm clock). It is bad idea. If you drive LED brightness from this PWM, it will blink unstable (sometimes with big pause).

I recommend use something like this http://focus.ti.com/docs/prod/folders/print/tlc5941.html
It has SPI controlled PWM dimmer (4096-step), no need to do it by software.

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