STM8 eForth WS2812 demo with tested timing

ws2812.fs

\ A STM8 eForth WS2812 demo with tested timing
\ 8 x WS2812B on PCB with 470µF capacitor at 5V supply
\ 3.3V MINDEV: PB4 with 1K pull-up to 5V works well

\res MCU: STM8S103
\res export PB_DDR PB_ODR PB_CR1

#require ]B!
#require ]CB

NVM
  \ transfer memory area a0.. a1 to a chain of WS2812
  : WS2812 ( a1 a0 -- )
     DO [
           $1601 ,         \     LDW  Y,(1,SP)
           $90F6 ,         \     LD   A,(Y)
           $88  C,         \     PUSH A
           $A608 ,         \     LD   A,#8
           HERE            \ 0$:
        ] [ 1 PB_ODR 4 ]B! [
           $0901 ,         \     RLC  (1,SP)
           $9D  C,         \     NOP
           $9D  C,         \     NOP
        ] [ PB_ODR 4 ]CB [
           $9D  C,         \     NOP
           $9D  C,         \     NOP
           $9D  C,         \     NOP
           $9D  C,         \     NOP
        ] [ 0 PB_ODR 4 ]B! [
           $9D  C,         \     NOP
           $4A  C,         \     DEC  A
           $4D  C,         \     TNZ  A
           $26  C,         \     JRNE ...
           HERE - 1- C,    \      ... 0$
           $84 C,          \     POP  A
        ]
     LOOP ;

  : init ( -- )
     [ 0 PB_ODR 4 ]B!
     [ 1 PB_DDR 4 ]B!
     [ 1 PB_CR1 4 ]B! ;
RAM

\\ Example

8 3 * CONSTANT #mem         \ memory for 8 x WS2812 
VARIABLE wsmem #mem 2- ALLOT 

\ simple test
: test ( n -- )
  init
  255 FOR
     wsmem #mem I FILL
     wsmem #mem + wsmem WS2812
     DUP FOR ( wait ) NEXT
  NEXT DROP ;

\ e.g. 10000 test