Update README.md

examples/systick_irq/README.md

@@ -4,11 +4,11 @@ interrupts for timing. Many bare-metal and RTOS based embedded applications will
 use the Systick IRQ for timing, periodic housekeeping and task arbitration so
 knowing how to set that up is useful.
 
-Note that this example is *NOT* compatible with the Delay_*() functions that are
-part of the ch32v003fun library - those functions use the Systick counter for
-doing busy-wait delays and assume that the CNT register rolls over at 32-bit
-maximum. Do not use the built-in Delay_Ms() and related functions when using
-Systick for IRQs.
+This code is compatible with the busywait delay functions in the ch32v003fun
+library because it allows the Systick CNT register to keep running over its full
+32-bit range. It does not set the STRE bit in the CTRL register so the counter
+does not reset when the CMP register matches. In order to do this, the CMP register
+is advanced at every IRQ.
 
 Note also the use of the  `__attribute__((interrupt))` syntax in declaring the
 IRQ handler. Some of the IRQ examples from the WCH HAL library have slightly