From a1f700efc1a39d4ee7df4297909a8d0567a87857 Mon Sep 17 00:00:00 2001
From: Martin Preuss <martin@aquamaniac.de>
Date: Sun, 19 Mar 2023 13:26:03 +0100
Subject: [PATCH] avr: add an initial wait time before starting the node.

This allows for desyncing of nodes to reduce COM collisions.
---
 avr/main.asm | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/avr/main.asm b/avr/main.asm
index aa254cc..b9e6a96 100644
--- a/avr/main.asm
+++ b/avr/main.asm
@@ -13,6 +13,10 @@ main:
   out SPL, r16             ; init LSB stack pointer
   
   rcall initModules
+
+  rcall Utils_SetupUid
+
+  rcall initialWait
   sei ; Enable interrupts
 
   rcall onSystemStart
@@ -271,6 +275,41 @@ sendValueMsg_done:
   ret
 
 
+
+; ---------------------------------------------------------------------------
+; initialWait
+;
+; Initial wait to desync nodes.
+;
+; This routine waits for between 10 to 2560 milliseconds (derived from UID)
+;
+; IN:
+; - nothing
+; OUT:
+; - nothing
+; USED: r16, r17, r18, r19, r20, r21, r22, X
+
+initialWait:
+  ; setup initial wait loop
+  rcall Utils_ReadUid             ; (R16, X)
+  clr r16
+  eor r16, r18
+  eor r16, r19
+  eor r16, r20
+  eor r16, r21
+
+initialWait_l1:    ; wait R16 x 10 milliseconds
+    ldi r17, 200
+initialWait_l2: ; wait for 10ms
+     Utils_WaitNanoSecs 50000, 0, r22 ; wait for 50 microseconds
+     dec r17
+    brne  initialWait_l2
+    dec r16
+  brne initialWait_l1
+  ret
+
+
+
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