From bc6d9072cec1c5e0b7d7d69ca584e03ed70a9140 Mon Sep 17 00:00:00 2001
From: Trevin Price <113460795+Trevin-Price@users.noreply.github.com>
Date: Sun, 29 Sep 2024 14:36:30 -0400
Subject: [PATCH 1/2] Fixed lpuart baud compute bug. Added secondary test.

---
 src/common/lpuart.rs | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/common/lpuart.rs b/src/common/lpuart.rs
index d656b8ad..55109bd3 100644
--- a/src/common/lpuart.rs
+++ b/src/common/lpuart.rs
@@ -593,8 +593,8 @@ impl Baud {
         let mut best_sbr = 0;
 
         let mut osr = 8;
-        let mut sbr = 1;
         while osr <= 32 {
+            let mut sbr = 1;
             while sbr < 8192 {
                 let b = source_clock_hz / (sbr * osr);
                 let e = max(baud, b) - min(baud, b);
@@ -1068,6 +1068,24 @@ mod tests {
         assert!(!BAUD.bothedge);
     }
 
+    #[test]
+    fn non_default_sbr_baud() {
+        // Assume the 24MHz XTAL clock.
+        const UART_CLOCK_HZ: u32 = 24_000_000;
+        // The best baud rate we can get is
+        const EXPECTED_BAUD: u32 = 9600;
+        // for a target baud of
+        const TARGET_BAUD: u32 = 9600;
+
+        const BAUD: Baud = Baud::compute(UART_CLOCK_HZ, TARGET_BAUD);
+
+        assert_eq!(BAUD.value(UART_CLOCK_HZ), EXPECTED_BAUD);
+
+        assert_eq!(BAUD.osr, 10, "OSR: {}", BAUD.osr);
+        assert_eq!(BAUD.sbr, 250, "SBR: {}", BAUD.sbr);
+        assert!(!BAUD.bothedge);
+    }
+
     #[test]
     fn read_data_flags() {
         let read_data = ReadData(1 << 15 | 1 << 13);

From cb1132a2c34f71f5e4e65046bf4566849863cfa9 Mon Sep 17 00:00:00 2001
From: Trevin Price <113460795+Trevin-Price@users.noreply.github.com>
Date: Sun, 29 Sep 2024 14:36:55 -0400
Subject: [PATCH 2/2] Increased max computable lpuart baud. Added associated
 test.

---
 src/common/lpuart.rs | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/common/lpuart.rs b/src/common/lpuart.rs
index 55109bd3..31a19b4a 100644
--- a/src/common/lpuart.rs
+++ b/src/common/lpuart.rs
@@ -592,7 +592,7 @@ impl Baud {
         let mut best_osr = 0;
         let mut best_sbr = 0;
 
-        let mut osr = 8;
+        let mut osr = if baud > 3_000_000 { 4 } else { 8 };
         while osr <= 32 {
             let mut sbr = 1;
             while sbr < 8192 {
@@ -1086,6 +1086,24 @@ mod tests {
         assert!(!BAUD.bothedge);
     }
 
+    #[test]
+    fn max_baud() {
+        // Assume the 24MHz XTAL clock.
+        const UART_CLOCK_HZ: u32 = 24_000_000;
+        // The best baud rate we can get is
+        const EXPECTED_BAUD: u32 = 6_000_000;
+        // for a target baud of
+        const TARGET_BAUD: u32 = 6_000_000;
+
+        const BAUD: Baud = Baud::compute(UART_CLOCK_HZ, TARGET_BAUD);
+
+        assert_eq!(BAUD.value(UART_CLOCK_HZ), EXPECTED_BAUD);
+
+        assert_eq!(BAUD.osr, 4, "OSR: {}", BAUD.osr);
+        assert_eq!(BAUD.sbr, 1, "SBR: {}", BAUD.sbr);
+        assert!(BAUD.bothedge);
+    }
+
     #[test]
     fn read_data_flags() {
         let read_data = ReadData(1 << 15 | 1 << 13);