From: Michael Gernoth <michael@gernoth.net>
Date: Mon, 23 Aug 2010 17:44:34 +0000 (+0200)
Subject: use tristate on outputs. Tested with a PC connected and everything works :-)
X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/commitdiff_plain/adc673c160ccdab692adbb59b9ddbf10bae8b206?ds=sidebyside;hp=989281f290d774ce78f71c8a420870987407a831

use tristate on outputs. Tested with a PC connected and everything works :-)
---

diff --git a/bmc/chassis.c b/bmc/chassis.c
index 2259d86..29541f2 100644
--- a/bmc/chassis.c
+++ b/bmc/chassis.c
@@ -31,7 +31,6 @@ static void chassis_set_pins(uint8_t pins, uint8_t state);
 void chassis_init()
 {
 	chassis_set_pins((1<<POWER_PIN) | (1<<RESET_PIN), 0);
-	CDDR |= ((1<<POWER_PIN) | (1<<RESET_PIN));
 
 	/* About 1ms */
 	OCR0 = ((F_CPU/64)/1000) - 1;
@@ -41,16 +40,27 @@ void chassis_init()
 
 }
 
+/* gracefully transition between tri-state and active */
 static void chassis_set_pins(uint8_t pins, uint8_t state)
 {
-#ifdef ACTIVE_LOW
-	state = !state;
-#endif
-
 	if(state) {
+		/* active */
+#ifndef ACTIVE_LOW
+		/* Pull UPs for a short moment... */
 		CPORT |= pins;
+#endif
+		CDDR |= pins;
+#ifdef ACTIVE_LOW
+		CPORT &= ~pins;
+#endif
 	} else {
+#ifdef ACTIVE_LOW
+		CPORT &= ~pins; /* NoOp... */
+#endif
+		CDDR &= ~pins;
+#ifndef ACTIVE_LOW
 		CPORT &= ~pins;
+#endif
 	}
 }