From da091b2ba2f48a5e3c207a04ee754100ae2f0836 Mon Sep 17 00:00:00 2001
From: ehushubhamshaw <eshaw1@wpi.edu>
Date: Wed, 4 Mar 2026 19:38:35 -0500
Subject: [PATCH] fix(aardvark-sys): i2c_scan ret > 0 to detect ACK, not >= 0

---
 crates/aardvark-sys/src/lib.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/crates/aardvark-sys/src/lib.rs b/crates/aardvark-sys/src/lib.rs
index 481364724..c2f630d36 100644
--- a/crates/aardvark-sys/src/lib.rs
+++ b/crates/aardvark-sys/src/lib.rs
@@ -310,7 +310,10 @@ impl AardvarkHandle {
         let mut buf = [0u8; 1];
         for addr in 0x08u16..=0x77 {
             let ret = unsafe { f(self.handle, addr, AA_I2C_NO_FLAGS, 1, buf.as_mut_ptr()) };
-            if ret >= 0 {
+            // ret > 0: bytes received → device ACKed
+            // ret == 0: NACK → no device at this address
+            // ret < 0: error code → skip
+            if ret > 0 {
                 found.push(addr as u8);
             }
         }