* thanks!  cool.  i can see the panic in a longer stack trace now.  

```
Frame 0: "HardFault handler. Cause: Escalated UsageFault (Undefined instruction)." @ 0x0006179c
Frame 1: __udf @ 0x0005efd6 inline
       ./asm/lib.rs:48:1
Frame 2: __udf @ 0x000000000005efd6
       ./asm/lib.rs:51:17
Frame 3: udf @ 0x00055956 inline
       /home/fuse117/.cargo/registry/src/index.crates.io-6f17d22bba15001f/cortex-m-0.7.7/src/asm.rs:43:5
Frame 4: hard_fault @ 0x0000000000055952
       /home/fuse117/.cargo/registry/src/index.crates.io-6f17d22bba15001f/panic-probe-0.3.1/src/lib.rs:86:5
Frame 5: panic @ 0x0005593c
       /home/fuse117/.cargo/registry/src/index.crates.io-6f17d22bba15001f/panic-probe-0.3.1/src/lib.rs:54:9
Frame 6: panic_fmt @ 0x0005f0b0
       /rustc/1fdfe1234795a289af1088aefa92ef80191cb611/library/core/src/panicking.rs:72:14
Frame 7: task_from_waker @ 0x0005e3ea inline
       /home/fuse117/.cargo/registry/src/index.crates.io-6f17d22bba15001f/embassy-executor-0.1.1/src/raw/waker.rs:43:9
```