Fix uart_interrupt example: enable RX interrupts in peripheral

The uart_interrupt example was not echoing received characters because
the RX interrupt enable bit (RIE) was not being set in the LPUART
control register. The NVIC interrupt was configured and the handler
was installed, but the peripheral itself was not generating interrupts.

Added uart.enable_rx_interrupts() call to enable RX data interrupts
in the LPUART2 peripheral before entering the main loop.

2 files changed, 7 insertions, 1 deletions

diff --git a/README.txt b/README.txt
index 80fa81b07..ae80ca8ef 100644
--- a/README.txt
+++ b/README.txt
@@ -287,6 +287,10 @@ probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-non
 probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/rtc_alarm
 probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/adc_polling
 probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/adc_interrupt
+probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/ostimer_alarm
+probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/ostimer_async
+probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/ostimer_counter
+probe-rs run --chip MCXA276 --protocol swd --speed 1000 target/thumbv8m.main-none-eabihf/debug/examples/ostimer_race_test
 ```
 
 How I tested on Windows
diff --git a/examples/uart_interrupt.rs b/examples/uart_interrupt.rs
index b309ce973..85743bb64 100644
--- a/examples/uart_interrupt.rs
+++ b/examples/uart_interrupt.rs
@@ -45,9 +45,11 @@ async fn main(_spawner: Spawner) {
     // Configure LPUART2 interrupt for UART operation BEFORE any UART usage
     hal::interrupt::LPUART2.configure_for_uart(hal::interrupt::Priority::from(3));
 
-    // Manually install the interrupt handler
+    // Manually install the interrupt handler and enable RX IRQs in the peripheral
     unsafe {
         hal::interrupt::LPUART2.install_handler(lpuart2_handler);
+        // Enable RX interrupts so the handler actually fires on incoming bytes
+        uart.enable_rx_interrupts();
     }
 
     // Print welcome message