bugfix: off-by-one for TX length

firmware/rust1/src/rs485.rs

@@ -246,7 +246,7 @@ impl RS485 {
         sm1.set_enable(true);
 
         let mut tx_data = [0, 'H' as u32, 'e' as u32, 'l' as u32, 'l' as u32, 'o' as u32, '\r' as u32, '\n' as u32];
-        tx_data[0] = (tx_data.len() - 1) as u32;
+        tx_data[0] = (tx_data.len() - 2) as u32;
         for i in 1..tx_data.len() {
             let x = tx_data[i] & 0xff;
             let mut parity = 0;
@@ -271,7 +271,11 @@ impl RS485 {
                 sm.rx().dma_pull(dma_in_ref.reborrow(), &mut din),
                 //debug_print_pio_addr(embassy_rp::pac::PIO0.sm(0)),
                 tx_future.continue_wait(),
-                rx_future.continue_wait(),
+                select(
+                    rx_future.continue_wait(),
+                    //debug_print_pio_addr(embassy_rp::pac::PIO0.sm(1)),
+                    core::future::pending::<()>(),
+                ),
             ).await;
             match x {
                 Either4::First(_) => {
@@ -360,7 +364,7 @@ impl RS485 {
                     drop(tx_future);
                     tx_future = DontAbort::new(sm1.tx().dma_push(dma_tx_ref.reborrow(), &tx_data));
                 },
-                Either4::Fourth(x) => {
+                Either4::Fourth(Either::First(x)) => {
                     drop(rx_future);
                     match x {
                         Result::Ok(()) => {