From: ian <ian>
Date: Wed, 21 Dec 2005 12:30:32 +0000 (+0000)
Subject: about updating fromserial only in serial rx isr
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=6acec26a68f57dfa02aa16e9eacbd9c26bb63323;p=trains.git

about updating fromserial only in serial rx isr
---

diff --git a/detpic/nmra-stream.asm b/detpic/nmra-stream.asm
index a101a76..7d01036 100644
--- a/detpic/nmra-stream.asm
+++ b/detpic/nmra-stream.asm
@@ -37,7 +37,9 @@ totrackbit	res	1	; bit location of pointer within byte
  ;
  ; fromserial points to the first empty byte, where we will put new
  ; data provided by the host; this means that (fromserial & 0xf0) is
- ; the first buffer which fails to contain a complete nmra message
+ ; the first buffer which fails to contain a complete nmra message.
+ ; fromserial is updated only by the (low priority) serial receive
+ ; interrupt handler.
  ;
  ; totrack points to the first remaining full byte, which is currently
  ; being transmitted; if nothing is currently being transmitted