Revised PSU switch-on circuit.

Updated notes on BMC and Audio sheet.

Author: thejpster

CHANGELOG.md

@@ -2,7 +2,10 @@
 
 ## Unreleased Changes
 
-* None
+* SYS_RESET is pulled down.
+* 5V PSU's `Ctrl` input is now controlled with PNP/NPN transistor pair.
+* Added extra explanatory text to BMC page
+* Added not on audio sheet about split grounds.
 
 ## v0.9.3
 

Kicad/Neotron-Common-Hardware-cache.lib

@@ -1501,11 +1501,11 @@ X VCC 8 0 400 100 D 50 50 1 1 W
 ENDDRAW
 ENDDEF
 #
-# Transistor_BJT_BC548
+# Transistor_BJT_BC546
 #
-DEF Transistor_BJT_BC548 Q 0 0 Y N 1 F N
+DEF Transistor_BJT_BC546 Q 0 0 Y N 1 F N
 F0 "Q" 200 75 50 H V L CNN
-F1 "Transistor_BJT_BC548" 200 0 50 H V L CNN
+F1 "Transistor_BJT_BC546" 200 0 50 H V L CNN
 F2 "Package_TO_SOT_THT:TO-92_Inline" 200 -75 50 H I L CIN
 F3 "" 0 0 50 H I L CNN
 ALIAS BC546 BC548 BC549 BC550 BC337 BC338
@@ -1525,6 +1525,29 @@ X E 3 100 -200 100 U 50 50 1 1 P
 ENDDRAW
 ENDDEF
 #
+# Transistor_BJT_BC556
+#
+DEF Transistor_BJT_BC556 Q 0 0 Y N 1 F N
+F0 "Q" 200 75 50 H V L CNN
+F1 "Transistor_BJT_BC556" 200 0 50 H V L CNN
+F2 "Package_TO_SOT_THT:TO-92_Inline" 200 -75 50 H I L CIN
+F3 "" 0 0 50 H I L CNN
+ALIAS BC556 BC558 BC559 BC560 BC327 BC328
+$FPLIST
+ TO?92*
+$ENDFPLIST
+DRAW
+C 50 0 111 0 1 10 N
+P 2 0 1 0 25 25 100 100 N
+P 3 0 1 0 25 -25 100 -100 100 -100 N
+P 3 0 1 20 25 75 25 -75 25 -75 N
+P 5 0 1 0 90 -70 70 -90 50 -50 90 -70 90 -70 F
+X C 1 100 200 100 D 50 50 1 1 P
+X B 2 -200 0 225 R 50 50 1 1 I
+X E 3 100 -200 100 U 50 50 1 1 P
+ENDDRAW
+ENDDEF
+#
 # power_+3.3V
 #
 DEF power_+3.3V #PWR 0 0 Y Y 1 F P
@@ -1640,4 +1663,19 @@ X pwr 1 0 0 0 U 50 50 0 0 w
 ENDDRAW
 ENDDEF
 #
+# power_VDC
+#
+DEF power_VDC #PWR 0 0 Y Y 1 F P
+F0 "#PWR" 0 -100 50 H I C CNN
+F1 "power_VDC" 0 250 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+DRAW
+P 2 0 1 0 -30 50 0 100 N
+P 2 0 1 0 0 0 0 100 N
+P 2 0 1 0 0 100 30 50 N
+X VDC 1 0 0 0 U 50 50 1 1 W N
+ENDDRAW
+ENDDEF
+#
 #End Library

Kicad/Neotron-Common-Hardware.sch

@@ -5,7 +5,7 @@ $Descr A4 11693 8268
 encoding utf-8
 Sheet 1 17
 Title "Neotron Common Hardware"
-Date "2021-04-02"
+Date "2021-04-06"
 Rev "[Uncontrolled]"
 Comp "https://neotron-compute.github.io/"
 Comment1 "Licenced as CC BY-SA"
@@ -1286,7 +1286,6 @@ NoConn ~ 9250 2775
 NoConn ~ 9250 2875
 NoConn ~ 9250 2975
 NoConn ~ 9250 3075
-NoConn ~ 10225 2475
 NoConn ~ 10225 2575
 NoConn ~ 10225 2675
 NoConn ~ 10225 2875
@@ -1301,4 +1300,5 @@ Text Notes 10275 3100 0    50   ~ 0
 Data Input
 Text Notes 10275 3200 0    50   ~ 0
 Am I Clear to Send?
+NoConn ~ 6100 925 
 $EndSCHEMATC

Kicad/audio.sch

@@ -1559,18 +1559,6 @@ Wire Wire Line
 Text Label 9900 1950 2    50   ~ 0
 5V0_ANALOG
 $Comp
-L power:PWR_FLAG #FLG0603
-U 1 1 60A6FC05
-P 4100 7100
-F 0 "#FLG0603" H 4100 7175 50  0001 C CNN
-F 1 "PWR_FLAG" V 4100 7227 50  0000 L CNN
-F 2 "" H 4100 7100 50  0001 C CNN
-F 3 "~" H 4100 7100 50  0001 C CNN
-	1    4100 7100
-	0    1    -1   0   
-$EndComp
-Connection ~ 4100 7100
-$Comp
 L power:GNDA #PWR0621
 U 1 1 5FE2BF79
 P 4000 4700
@@ -2361,8 +2349,12 @@ Wire Wire Line
 Connection ~ 7100 3750
 Wire Wire Line
 	7100 3750 7450 3750
-Text Notes 5100 5975 0    50   ~ 0
+Text Notes 5250 6250 0    50   ~ 0
 The TLV320AIC23 must be set to:\n1) USB Mode (12 MHz clock)\n2) So-called 'Slave' mode (LRCOUT, LRCIN and BCLK are inputs)
 Wire Wire Line
 	3500 7100 4100 7100
+Text Notes 4850 7700 0    50   ~ 0
+Some texts will tell you to 'split' GND and GNDA, in\norder to reduce noise, and that you should join them\nonly at a single point using a Ferrite Bead or a\nResistor. Others will tell you that attempting to carve\nyour ground plane like this will cause terrible EMI as\nyou will inevitably have traces crossing the split in\nthe ground plane, making the return current take the\nlong way back.\n\nBecause the TLV320AIC23 does not present 'analog'\npins on one side and 'digital' pins on the other\n(thus not lending itself towards straddling a split\nground plane), I've elected to follow the latter idiom.
+Wire Notes Line
+	4800 6550 6950 6550
 $EndSCHEMATC

Kicad/bmc.sch

@@ -4,12 +4,12 @@ EELAYER END
 $Descr A4 11693 8268
 encoding utf-8
 Sheet 16 17
-Title ""
+Title "Neotron Common Hardware - Board M'gmt Controller"
 Date ""
-Rev ""
-Comp ""
-Comment1 ""
-Comment2 ""
+Rev "[Uncontrolled]"
+Comp "https://neotron-compute.github.io/"
+Comment1 "Licenced as CC BY-SA"
+Comment2 "Copyright (c) The Neotron Developers, 2021"
 Comment3 ""
 Comment4 ""
 $EndDescr
@@ -28,8 +28,6 @@ F 3 "" H 2925 3850 50  0001 C CNN
 $EndComp
 Text Notes 3975 4075 2    50   Italic 0
 Manual reset switch:\nTap to reboot host
-Text Notes 7600 1200 0    50   ~ 0
-The BMC controls power/reset, as well\nas PS/2 devices and performing voltage\nrail monitoring.\n\nLines to host are hi-Z until host is\npowered (i.e. 3.3V looks good) to\navoid back-powering.
 $Comp
 L Device:C C1603
 U 1 1 606E29E5
@@ -349,29 +347,29 @@ PS2_DAT1
 $Comp
 L Device:Jumper_NO_Small JP1601
 U 1 1 6072F924
-P 2600 1875
-F 0 "JP1601" H 2600 2060 50  0000 C CNN
-F 1 "Jumper" H 2600 1969 50  0000 C CNN
-F 2 "Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical" H 2600 1875 50  0001 C CNN
-F 3 "~" H 2600 1875 50  0001 C CNN
-F 4 "1" H 2600 1875 50  0001 C CNN "DNP"
-F 5 "~" H 2600 1875 50  0001 C CNN "Digikey"
-F 6 "~" H 2600 1875 50  0001 C CNN "MPN"
-F 7 "~" H 2600 1875 50  0001 C CNN "Manufacturer"
-	1    2600 1875
+P 3800 1875
+F 0 "JP1601" H 3800 2060 50  0000 C CNN
+F 1 "Jumper" H 3800 1969 50  0000 C CNN
+F 2 "Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical" H 3800 1875 50  0001 C CNN
+F 3 "~" H 3800 1875 50  0001 C CNN
+F 4 "1" H 3800 1875 50  0001 C CNN "DNP"
+F 5 "~" H 3800 1875 50  0001 C CNN "Digikey"
+F 6 "~" H 3800 1875 50  0001 C CNN "MPN"
+F 7 "~" H 3800 1875 50  0001 C CNN "Manufacturer"
+	1    3800 1875
 	1    0    0    -1  
 $EndComp
 Wire Wire Line
 	6125 1350 6125 1425
 $Comp
 L power:+3.3VP #PWR01607
 U 1 1 606E2A06
-P 2250 1825
-F 0 "#PWR01607" H 2400 1775 50  0001 C CNN
-F 1 "+3.3VP" H 2250 1975 50  0000 C CNN
-F 2 "" H 2250 1825 50  0001 C CNN
-F 3 "" H 2250 1825 50  0001 C CNN
-	1    2250 1825
+P 3425 1825
+F 0 "#PWR01607" H 3575 1775 50  0001 C CNN
+F 1 "+3.3VP" H 3425 1975 50  0000 C CNN
+F 2 "" H 3425 1825 50  0001 C CNN
+F 3 "" H 3425 1825 50  0001 C CNN
+	1    3425 1825
 	1    0    0    -1  
 $EndComp
 Text Label 4425 1250 0    50   ~ 0
@@ -481,7 +479,7 @@ Wire Wire Line
 Wire Wire Line
 	6325 1425 6325 1475
 Wire Wire Line
-	2250 1825 2250 1875
+	3425 1825 3425 1875
 Wire Wire Line
 	5625 2575 5275 2575
 Wire Wire Line
@@ -505,7 +503,7 @@ Wire Wire Line
 Text Notes 3425 1400 0    50   Italic 0
 Serial Wire Debug
 Wire Wire Line
-	2700 1875 2850 1875
+	3900 1875 4100 1875
 Wire Wire Line
 	6725 2975 7225 2975
 Wire Wire Line
@@ -670,7 +668,7 @@ MON_5V
 Text Label 8375 1975 2    50   ~ 0
 MON_3V3
 Wire Wire Line
-	2250 1875 2500 1875
+	3425 1875 3700 1875
 Wire Wire Line
 	9925 5375 10675 5375
 Connection ~ 9925 5375
@@ -751,7 +749,7 @@ Wire Wire Line
 	6725 2575 7075 2575
 Wire Wire Line
 	6725 2675 7075 2675
-Text Notes 2025 1500 0    50   Italic 0
+Text Notes 2650 2100 0    50   Italic 0
 Fit jumper to enable UART\nbootloader on PA9/PA10
 Wire Wire Line
 	8025 1975 8475 1975
@@ -789,16 +787,16 @@ $EndComp
 $Comp
 L Device:R R1605
 U 1 1 606E29F2
-P 2850 2125
-F 0 "R1605" H 2800 2175 50  0000 R CNN
-F 1 "10k 1%" H 2800 2075 50  0000 R CNN
-F 2 "Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder" V 2780 2125 50  0001 C CNN
-F 3 "~" H 2850 2125 50  0001 C CNN
-F 4 "0" H 2850 2125 50  0001 C CNN "DNP"
-F 5 "RMCF0805FT10K0-ND" H 2850 2125 50  0001 C CNN "Digikey"
-F 6 "RMCF0805FT10K0" H 2850 2125 50  0001 C CNN "MPN"
-F 7 "Stackpole" H 2850 2125 50  0001 C CNN "Manufacturer"
-	1    2850 2125
+P 4100 2125
+F 0 "R1605" H 4050 2175 50  0000 R CNN
+F 1 "10k 1%" H 4050 2075 50  0000 R CNN
+F 2 "Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder" V 4030 2125 50  0001 C CNN
+F 3 "~" H 4100 2125 50  0001 C CNN
+F 4 "0" H 4100 2125 50  0001 C CNN "DNP"
+F 5 "RMCF0805FT10K0-ND" H 4100 2125 50  0001 C CNN "Digikey"
+F 6 "RMCF0805FT10K0" H 4100 2125 50  0001 C CNN "MPN"
+F 7 "Stackpole" H 4100 2125 50  0001 C CNN "Manufacturer"
+	1    4100 2125
 	1    0    0    -1  
 $EndComp
 $Comp
@@ -1083,8 +1081,6 @@ Wire Wire Line
 	4825 2375 5625 2375
 Wire Wire Line
 	4825 2375 4825 3725
-Wire Wire Line
-	6725 1875 7075 1875
 Wire Wire Line
 	6725 1975 7075 1975
 Text Notes 900  1425 0    50   ~ 0
@@ -1096,23 +1092,23 @@ For case LED
 Wire Wire Line
 	7225 1000 7225 2975
 Wire Wire Line
-	2850 1875 5625 1875
-Connection ~ 2850 1875
+	4100 1875 5625 1875
+Connection ~ 4100 1875
 Wire Wire Line
-	2850 1875 2850 1975
+	4100 1875 4100 1975
 $Comp
 L power:GND #PWR0133
 U 1 1 6086D93C
-P 2850 2350
-F 0 "#PWR0133" H 2850 2100 50  0001 C CNN
-F 1 "GND" H 2855 2177 50  0000 C CNN
-F 2 "" H 2850 2350 50  0001 C CNN
-F 3 "" H 2850 2350 50  0001 C CNN
-	1    2850 2350
+P 4100 2325
+F 0 "#PWR0133" H 4100 2075 50  0001 C CNN
+F 1 "GND" H 4105 2152 50  0000 C CNN
+F 2 "" H 4100 2325 50  0001 C CNN
+F 3 "" H 4100 2325 50  0001 C CNN
+	1    4100 2325
 	-1   0    0    -1  
 $EndComp
 Wire Wire Line
-	2850 2350 2850 2275
+	4100 2325 4100 2275
 Text Notes 900  2375 0    50   ~ 0
 TTL UART
 Text HLabel 1025 2125 2    50   Output ~ 0
@@ -1145,8 +1141,6 @@ Text Label 975  2625 2    50   ~ 0
 DC_ON
 Wire Wire Line
 	1025 2625 675  2625
-Text HLabel 1025 2625 2    50   Output ~ 0
-DC_ON
 Text Label 975  2525 2    50   ~ 0
 ~SYS_RESET
 Wire Wire Line
@@ -1161,4 +1155,52 @@ Text HLabel 1025 2525 2    50   Output ~ 0
 ~RESET
 Wire Wire Line
 	1025 2225 600  2225
+$Comp
+L Device:R R1611
+U 1 1 6071F9F2
+P 8000 3950
+F 0 "R1611" H 8070 3996 50  0000 L CNN
+F 1 "10k 1%" H 8070 3905 50  0000 L CNN
+F 2 "Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder" V 7930 3950 50  0001 C CNN
+F 3 "~" H 8000 3950 50  0001 C CNN
+F 4 "0" H 8000 3950 50  0001 C CNN "DNP"
+F 5 "RMCF0805FT10K0-ND" H 8000 3950 50  0001 C CNN "Digikey"
+F 6 "RMCF0805FT10K0" H 8000 3950 50  0001 C CNN "MPN"
+F 7 "Stackpole" H 8000 3950 50  0001 C CNN "Manufacturer"
+	1    8000 3950
+	-1   0    0    -1  
+$EndComp
+Wire Wire Line
+	8000 3725 8000 3800
+Wire Wire Line
+	8000 4100 8000 4150
+$Comp
+L power:GND #PWR01610
+U 1 1 607270B5
+P 8000 4150
+F 0 "#PWR01610" H 8000 3900 50  0001 C CNN
+F 1 "GND" H 8005 3977 50  0000 C CNN
+F 2 "" H 8000 4150 50  0001 C CNN
+F 3 "" H 8000 4150 50  0001 C CNN
+	1    8000 4150
+	-1   0    0    -1  
+$EndComp
+Wire Wire Line
+	6725 1875 7075 1875
+Text Label 7950 3725 2    50   ~ 0
+~SYS_RESET
+Wire Wire Line
+	7750 3725 8000 3725
+Text Notes 8100 4025 0    50   Italic 0
+System is in reset by default,\nunless STM32 drives SYS_RESET high.
+Text Notes 1375 2550 0    50   Italic 0
+Everything held in reset when low
+Text Notes 1375 2650 0    50   Italic 0
+Turns on main 5V rail when high
+Text HLabel 1025 2625 2    50   Output ~ 0
+DC_ON
+Text Notes 1375 2750 0    50   Italic 0
+Need service when level is high
+Text Notes 550  7700 0    79   Italic 0
+This STM32 runs on the permanent 3.3VP power rail.\nIt boots up as soon as the board has power connected.\nIt handles the power button and reset buttons, and\ncontrols the main DC-DC PSU and the system reset lines.\nIt has an I²C bus, two LED outputs, a four-wire UART, and\ntwo PS/2 ports. It can monitor both 3.3V and 5.0V power\nrails. It talks to the host over SPI.\n\nLines to host are hi-Z until host is powered\n(i.e. 5V and 3.3V look good) to avoid back-powering.
 $EndSCHEMATC