From e70be9e17a000cbe1e55e037a8eb5c8f8588fcd9 Mon Sep 17 00:00:00 2001
From: vadim <vadim@flytrex.com>
Date: Fri, 1 Mar 2019 11:42:33 +0200
Subject: [PATCH] filter out zero encoder reading - can be caused by gnd short

---
 encoder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/encoder.c b/encoder.c
index 3d656bd2..0004867f 100644
--- a/encoder.c
+++ b/encoder.c
@@ -334,7 +334,7 @@ void encoder_tim_isr(void) {
 		spi_end();
 
 		spi_val = pos;
-		if(spi_check_parity(pos) && pos!=0xffff) {
+		if(spi_check_parity(pos) && pos!=0xffff && pos!=0) {  // all ones = disconnect, all zeros = short to gnd
 			pos &= 0x3FFF;
 			last_enc_angle = ((float)pos * 360.0) / 16384.0;
 			UTILS_LP_FAST(spi_error_rate, 0.0, 1./AS5047_SAMPLE_RATE_HZ);