Hi,
if I understood the datasheet correct, 24 bits are reqired to set the color of the LED. 8 bit for the red value, 8 bit for the blue value and 8 bit for green.
According to the sequence chart on page 4 a time of 800 ns ~ 1.38 µs is required to set a single bit (T0H + T1H or T0L + T1L). The smallest time instance is 220 ns which corresponds to a frequency of ~4.55 MHz. Which should not be a problem with a STM32F if not operated at a low frequency.
As the 5 LEDs are wired in series, they are daisy chained. Consequently it takes more time until the last LED receives the intended color information, as its information is shifted through the registers of the previous LEDs. So you have to send the color information of the 5th LED first followed by the color of the 4th and so on.
So basically the only information you are interested in is the minimum microcontroller wait time of 220 ns ~ 380 ns (as it seems you are aiming to communicate by bit banging). The overall time untill all 5 LEDs are correctly set shoud last (800 ns ~ 1.38 µs) • Numbers of LEDs • Data length = (800 ns ~ 1.38 µs) • 5 • 24 = 96 µs ~ 165.6 µs.
greets