From 7e21224c6976a6f3e618e5ed502bf8f2503f6ee0 Mon Sep 17 00:00:00 2001
From: Drahoslav <drahoslav@yo2.cz>
Date: Thu, 16 Nov 2017 01:47:08 +0100
Subject: [PATCH] Do not change mash while busy

---
 rpio.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rpio.go b/rpio.go
index 5fc9b58..c6778ce 100644
--- a/rpio.go
+++ b/rpio.go
@@ -345,7 +345,7 @@ func SetFreq(pin Pin, freq int) {
 	const enab = 1 << 4
 	const src = 1 << 0 // oscilator
 
-	clkMem[clkCtlReg] = PASSWORD | src // stop gpio clock
+	clkMem[clkCtlReg] = PASSWORD | (clkMem[clkCtlReg] &^ enab) // stop gpio clock (without changing src or mash)
 	for clkMem[clkCtlReg]&busy != 0 {
 		time.Sleep(time.Microsecond * 10)
 	} // ... and wait for not busy