[commit] r2661 - cpu/arm/olpc/1.75

[repository service]

Author: quozl
Date: Tue Nov  1 06:37:37 2011
New Revision: 2661
URL: http://tracker.coreboot.org/trac/openfirmware/changeset/2661

Log:
OLPC XO-1.75 - wait for data to be available at the accelerometer before reading it.  Side effect of doubling test time to five seconds.  Removes some positional jitter in roller caused by the low and high bytes being from different samples.

Modified:
   cpu/arm/olpc/1.75/accelerometer.fth

Modified: cpu/arm/olpc/1.75/accelerometer.fth
==============================================================================
--- cpu/arm/olpc/1.75/accelerometer.fth	Tue Nov  1 06:32:03 2011	(r2660)
+++ cpu/arm/olpc/1.75/accelerometer.fth	Tue Nov  1 06:37:37 2011	(r2661)
@@ -15,6 +15,7 @@
 : accelerometer-off  ( -- )  h# 07 ctl1!  ;
 : wext  ( b -- n )  dup h# 8000 and  if  h# ffff0000 or  then  ;
 : acceleration@  ( -- x y z )
+   begin  h# 27 acc-reg@  h# 08 and  until  \ wait for data available
    h# 28 acc-reg@ h# 29 acc-reg@ bwjoin wext 5 >>a
    h# 2a acc-reg@ h# 2b acc-reg@ bwjoin wext 5 >>a
    h# 2c acc-reg@ h# 2d acc-reg@ bwjoin wext 5 >>a