From 4e1230ec3c4a39294cc526bb8655131b97b06d08 Mon Sep 17 00:00:00 2001
From: Viktor Sonesten <viktor.sonesten@grepit.se>
Date: Thu, 13 Jan 2022 17:44:42 +0100
Subject: [PATCH] itm: configure: set ITMENA after TraceBusID

Related to #392.
---
 src/peripheral/itm.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/peripheral/itm.rs b/src/peripheral/itm.rs
index b3e8bd9f..db08b84d 100644
--- a/src/peripheral/itm.rs
+++ b/src/peripheral/itm.rs
@@ -340,11 +340,14 @@ impl ITM {
 
         unsafe {
             self.tcr.modify(|mut r| {
-                r.set_itmena(settings.enable);
                 r.set_tsena(settings.local_timestamps != LocalTimestampOptions::Disabled);
                 r.set_txena(settings.forward_dwt); // forward hardware event packets from the DWT to the ITM
                 r.set_tracebusid(settings.bus_id.unwrap_or(0));
 
+                // must be modified after TraceBusID, see last section in
+                // <https://developer.arm.com/documentation/ddi0403/d/Debug-Architecture/ARMv7-M-Debug/The-Instrumentation-Trace-Macrocell/Trace-Control-Register--ITM-TCR?lang=en>
+                r.set_itmena(settings.enable);
+
                 r
             });
         }