Expand is_debugger_attached note
@@ -34,13 +34,16 @@ impl DCB {
// unset bit 24 / TRCENA
unsafe { self.demcr.modify(|w| w & !DCB_DEMCR_TRCENA); }
- /// Is there a debugger attached? (see note)
+ /// Is there a debugger attached? (see notes)
///
- /// N.B. This function is [reported not to
+ /// Note 1: This function is [reported not to
/// work](http://web.archive.org/web/20180821191012/https://community.nxp.com/thread/424925#comment-782843)
/// on Cortex-M0 devices. Per the ARM v6-M Architecture Reference Manual, "Access to the DHCSR
/// from software running on the processor is IMPLEMENTATION DEFINED". Indeed, from the
/// [Cortex-M0+ r0p1 Technical Reference Manual](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0484c/BABJHEIG.html), "Note Software cannot access the debug registers."
+ ///
+ /// Note 2: This function reads the DHCSR register, and therefore clears S_RESET_ST and
+ /// S_RETIRE_ST.
pub fn is_debugger_attached() -> bool {
unsafe { (*Self::ptr()).dhcsr.read() & 0x1 == 1 }
}
