From 4f04bf17a8c1f27f7385aceaa19a2f460799d610 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Robert=20J=C3=B6rdens?= <rj@quartiq.de>
Date: Wed, 21 Jul 2021 13:29:13 +0200
Subject: [PATCH] signal_generator: also reject negative frequencies

---
 src/hardware/signal_generator.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/hardware/signal_generator.rs b/src/hardware/signal_generator.rs
index e117423..cc05475 100644
--- a/src/hardware/signal_generator.rs
+++ b/src/hardware/signal_generator.rs
@@ -77,7 +77,7 @@ impl TryFrom<BasicConfig> for Config {
 
         // Validate base frequency tuning word to be below Nyquist.
         const NYQUIST: f32 = (1u32 << 31) as _;
-        if 2.0 * ftw > NYQUIST {
+        if ftw < 0.0 || 2.0 * ftw > NYQUIST {
             return Err(Error::InvalidFrequency);
         }