nrf: don't block SPI transfer

aykevl · aykevl · commit f95e7653e2ae · 2025-11-16T08:50:09.000+01:00
Ideally we'd use something like #5016 but that's a bit more involved. As a quick improvement, call gosched() instead. Example where I use this: a custom WS2812 driver that uses SPI to transfer the data. It's useful to be able to switch back to the main goroutine during the transfer to render the next LED update.
diff --git a/src/machine/machine_nrf52xxx.go b/src/machine/machine_nrf52xxx.go
@@ -335,6 +335,7 @@ func (spi *SPI) Tx(w, r []byte) error {
 		// finished if the transfer is send-only (a common case).
 		spi.Bus.TASKS_START.Set(1)
 		for spi.Bus.EVENTS_END.Get() == 0 {
+			gosched()
 		}
 		spi.Bus.EVENTS_END.Set(0)
 	}

Original file line number	Diff line number	Diff line change
`@@ -335,6 +335,7 @@ func (spi *SPI) Tx(w, r []byte) error {`
`335`	`335`	`// finished if the transfer is send-only (a common case).`
`336`	`336`	`spi.Bus.TASKS_START.Set(1)`
`337`	`337`	`for spi.Bus.EVENTS_END.Get() == 0 {`
	`338`	`+ gosched()`
`338`	`339`	`}`
`339`	`340`	`spi.Bus.EVENTS_END.Set(0)`
`340`	`341`	`}`