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| author | Ayke van Laethem <[email protected]> | 2020-06-08 16:25:31 +0200 |
|---|---|---|
| committer | Ron Evans <[email protected]> | 2020-06-08 19:54:41 +0200 |
| commit | 169d5f17b879a05145ce47ea4fb4af898b23b9d8 (patch) | |
| tree | 54d35e7817c938557712c6da7c5eec622caf4668 /src | |
| parent | 9ed5eae6a939541b73dfcf2786cee3188ec6b125 (diff) | |
| download | tinygo-169d5f17b879a05145ce47ea4fb4af898b23b9d8.tar.gz tinygo-169d5f17b879a05145ce47ea4fb4af898b23b9d8.zip | |
nrf: fix bug in SPI.Tx
There was what appears to be a race condition in the Tx function. While
it would work fine in many cases, when there were interrupts (such as
when using BLE), the function would just hang waiting for `EVENTS_READY`
to arrive.
I think what was happening was that the `spi.Bus.RXD.Get()` would start
the next transfer, which would complete (and generate an event) before
`EVENTS_READY` was reset to 0. The fix is easy: clear `EVENTS_READY`
before doing something that can trigger an event.
I believe I've seen this bug before on the PineTime but I couldn't find
the issue back then.
Diffstat (limited to 'src')
| -rw-r--r-- | src/machine/machine_nrf.go | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/machine/machine_nrf.go b/src/machine/machine_nrf.go index 382dd05c2..3d65ad578 100644 --- a/src/machine/machine_nrf.go +++ b/src/machine/machine_nrf.go @@ -443,13 +443,13 @@ func (spi SPI) Tx(w, r []byte) error { spi.Bus.TXD.Set(uint32(b)) for spi.Bus.EVENTS_READY.Get() == 0 { } - _ = spi.Bus.RXD.Get() spi.Bus.EVENTS_READY.Set(0) + _ = spi.Bus.RXD.Get() } for spi.Bus.EVENTS_READY.Get() == 0 { } - _ = spi.Bus.RXD.Get() spi.Bus.EVENTS_READY.Set(0) + _ = spi.Bus.RXD.Get() default: // write/read |