I have done some speed tests and found that I can refresh 8 bytes to a 595 at +- 68Khz which translates to +- 5.4Mhz as the bit level. This includes the latching and using SPI at divisor/2.
Is this the fastest refresh rate one can expect from shift registers?
I am stuck between choosing a TLC5450 and TPIC6B596 for a rotating persistence of vision display. It seems to me that with the current timing I am getting, shifting 12 bits per LED for the TLC5940 will be pushing the limits of my refresh requirements which is 64 LEDs at 2Khz.
The TLC's 'strange' 4096 tick interval on the PWM gray scale clock for refresh of data may also complicate matters in a system that is already very much fixed interval orientated. Can I even get the 16MHz clock of the arduino out to the TLC5450 to achieve a 3.9KHz refresh?