Need latching PWM demux

[artec_19]

I want to split 2 independent PWM signals into 4 independent PWM signals.

The ideal IC would have 2 PWM inputs, 1 selector bit, 4 PWM outputs (2 ports of 2 PWM outputs), and a latch that maintains the previously commanded output whenever a pair of outputs (port) is not selected.

Does such an IC exist? I know I could do it with a PIC or something similar, but I would rather not if something already exists.

I found this: https://www.electro-tech-online.com/custompdfs/2009/12/tlc5940.pdf
but that uses a single serial input, and that will not be fast enough for my application.

Also: https://www.electro-tech-online.com/custompdfs/2009/12/tlc5904.pdf
but I believe this takes an 8-bit digital in, and I do not have enough free GPIOs to do that.

Any suggestions?

 

[Nigel Goodwin]

You need to give more details, possible solutions will depend on the exact application.

 

[artec_19]

It is for PID control of 4 DC motors. I have 2 hardware pwm outputs, and limited digital GPIOs. The pwm lines go to motor drivers. Currently the system has 2 DC motors, with a PID loop (and all data collecting) closed at 2kHz (for both motors). The idea was to split the pwm lines to portA and portB, and update a particular port every other loop: thus reducing the control rate to 1kHz (which is still acceptable).

I am using a gumstix basix to run this, and i2c seems to take about 0.25ms: which is way too long.

5V or 3.3V does not matter.