remove/add comments

2 files changed, 44 insertions, 29 deletions

diff --git a/hardware.h b/hardware.h
index 99e7334..56b8782 100644..100755
--- a/hardware.h
+++ b/hardware.h
@@ -67,11 +67,22 @@
 PxOUT_INIT                    //Init Output data of portx
 PxDIR_INIT                    //Init of Portx Data-Direction Reg (Out=1 / Inp=0)
 PxSEL_INIT                    //Px-Modules:
-PxREN_INIT                    // Pull up resistor
+PxREN_INIT                    //Pull up resistor
 PxIE_INIT                     //Interrupt Enable (0=dis 1=enabled)
 PxIES_INIT                    //Interrupt Edge Select (0=pos 1=neg)
 */
 
+// NOTES:
+//
+// * V1P2_CORE_EN_N is initialized as an output high for a reason!
+//
+// ATX specifies that there can be as much as 20 ms between 5V reaching
+// its 95% level and 3.3V doing likewise. U5H1 (ISL6545) is powered by
+// 5V and Q5U1, that disables it, has a pull-up 3.3V on its gate.
+// ISL6545 can ramp up its output between ~ 10 and 17 ms (and might
+// do it even before) after Power On Reset.
+
+
 // PORT1
 #define P1OUT_INIT      (START_SW1_N | RST_SW2_N | V1P2_CORE_EN_N)
 #define P1DIR_INIT      (V1P2_CORE_EN_N)
diff --git a/main.c b/main.c
index 72b701a..a38d37f 100644..100755
--- a/main.c
+++ b/main.c
@@ -82,10 +82,10 @@ int main(void)
   while (1) {
     switch (state) {
     case WAIT_START:
-      if (SW1State > 30) // SW1 pressed for at least 30ms
+      if (SW1State > 30)
         state = WAIT_START + 1;
       break;
-    case WAIT_START + 1: // wait for release SW1 before real Start
+    case WAIT_START + 1:
       if (SW1State == 0) {
         SetBit(P4OUT, CMDPWR); // Start Atx Power Supply
         Timer1 = 2000;
@@ -95,13 +95,12 @@ int main(void)
 
     case WAIT_ATX_OK:
       if (SW1State || TENSION_EXPIRED)
-        state = STOP; // if SW1 just pressed during power or ATX didn't set up
-                      // ATX power OK, stop
+        state = STOP;
       if ((P4IN & ATX_PWROK) && TENSION_WAIT(bV2P5 && bVCC3)) {
-        // atx power Ok & V2P5 Ok
-        SetBit(P1DIR, V1P2_CORE_EN_N); // enable V1P2 (V1P2_CORE_EN_N go from
-                                       // Hz to Out Low)
-        Timer1 = 30; // set Timer1 @ 30 milli seconde to get V1P2 stable
+        // assertion: V1P2_CORE_EN_N is low but high impedance here
+        // TO CHECK
+        SetBit(P1DIR, V1P2_CORE_EN_N);
+        Timer1 = 30;
         state = WAIT_V1P2;
       }
       break;
@@ -109,9 +108,9 @@ int main(void)
     case WAIT_V1P2:
       if (SW1State || TENSION_EXPIRED)
         state = STOP;
-      if (TENSION_WAIT(bV1P2)) { // Got V1P2 stable
-        Timer1 = 30; // set Timer1 @ 30 milli seconde to get V1P8-DDR stable
-        SetBit(P4OUT, V1P8_CMD); // enable V1P8-DDR
+      if (TENSION_WAIT(bV1P2)) {
+        Timer1 = 30;
+        SetBit(P4OUT, V1P8_CMD);
         state = WAIT_RSMRST;
       }
       break;
@@ -130,8 +129,8 @@ int main(void)
       if (SW1State || TENSION_EXPIRED)
         state = STOP;
       if (TENSION_WAIT(bV1P8)) {
-        ClrBit(P2OUT, CPU_VCCP_EN_N); // enable V1P0
-        Timer1 = 30; // set Timer1 @ 30 milli seconde to get V1P0 stable
+        ClrBit(P2OUT, CPU_VCCP_EN_N);
+        Timer1 = 30;
         state = WAIT_V1P0;
       }
       break;
@@ -139,51 +138,56 @@ int main(void)
     case WAIT_V1P0:
       if (SW1State || TENSION_EXPIRED)
         state = STOP;
-      if (TENSION_WAIT(bV1P0)) { // Got V1P0 stable and all other supplies too
+      if (TENSION_WAIT(bV1P0)) {
         SetBit(P3OUT, VRMPWRGD);
-        ClrBit(P2OUT, GREEN_LED_N); // set GREEN_LED_N to show Power Seq Ok
-        Timer1 = 3; // set Timer1 @ 3ms instead of 2 before assserted
-                    // CK410_PWR_GD_N Low
+        ClrBit(P2OUT, GREEN_LED_N);
+        Timer1 = 3;
         state = CK410_VTT_GD;
       }
       break;
 
     case CK410_VTT_GD:
       if (Timer1 == 0) {
-        SetBit(P2DIR, CK410_PWR_GD_N); // asssert CK410_PWR_GD_N As output
-        ClrBit(P2OUT, CK410_PWR_GD_N); // asssert CK410_PWR_GD_N Low
-        Timer1 = 300; // set Timer1 @ 300 ms before starting Tolapai
+        SetBit(P2DIR, CK410_PWR_GD_N);
+        ClrBit(P2OUT, CK410_PWR_GD_N);
+        Timer1 = 300;
         state = CPU_RUN;
       }
       break;
 
     case CPU_RUN:
-      if (SW1State) // if SW1 just pressed during power up go STOP
+      if (SW1State)
         state = STOP;
       if (Timer1 == 0) {
-        SetBit(P2DIR, IMCH_PWRBTN_N); // Start Tolapai
-        Timer1 = 200; // pour relācher le bouton comme un humain
+        // Start Tolapai: emulate the power button from its point of view
+        // we don't really know where is the best place to do that so
+        // we will try it here at first.
+        SetBit(P2DIR, IMCH_PWRBTN_N);
+        Timer1 = 200;
         state = CPU_RUN + 1;
       }
       break;
     case CPU_RUN + 1:
-      if (SW1State) // if SW1 just pressed during power up go STOP
+      if (SW1State)
         state = STOP;
       if (Timer1 == 0) {
-        ClrBit(P2DIR, IMCH_PWRBTN_N); // Release IMCH-PWRBTN-N signal after 200
-                                     // milli-secondes
+        ClrBit(P2DIR, IMCH_PWRBTN_N);
         state = WAIT_STOP;
       }
       break;
 
     case WAIT_STOP:
-      if (SW1State >= 6000) // Sw1 button press for more than 6 secondes
+      if (SW1State >= 6000) // Sw1 button pressed for more than 6 secondes
         state = STOP;
       break;
 
     case STOP:
       InitPorts();
-      Timer1 = 10000; // set Timer1 @ 10s before any other Power up
+      Timer1 = 10000; // Disable any other Power up for 10s.
+      // We are very careful at first but we know no reason why this should
+      // not work with an extremely lower timer. Under some conditions ATX
+      // imposes debouncing up to at least 100 ms. I guess a good compromise
+      // would be somewhere between 0.5 to 1s.
       ClrBit(P2OUT, RED_LED_N); // To show no restart is possible for now
       state = STOP + 1;
       break;