schematics: additional comments for wifi bootstrapping and readme update

README.md

@@ -126,3 +126,6 @@ Make the prototype.
     [x] 25MHz oscillator: needs clearance from LEDs, move under USB1
     [ ] connect SPI Flash Quad Mode (QSPI)
     [x] connect SHUTDOWN to FPGA
+    [ ] ESP-32: GPIO12 at boot selects internal flash voltage,
+        it is connected to J1_27+ and wrong pullup/pulldown at boot
+        will prevent ESP32 from booting

power.bak

@@ -1951,4 +1951,6 @@ F 3 "" H 10900 2750 50  0001 C CNN
 $EndComp
 Text Notes 5100 5300 0    60   ~ 0
 Switching regulators 2A SOT23-5\nTexas instruments TLV62569DBV (2A)\nMicrosemi LX7172 (1.2A)\nDioo microcircuits DIO6015 (1.5A)\nDiodes AP3429/A (2A) - will it meet spec?
+Text Notes 1000 5400 0    60   ~ 0
+SHUTDOWN connected to\nBANK2 on "ram" sheet
 $EndSCHEMATC

power.sch

@@ -1951,4 +1951,6 @@ F 3 "" H 10900 2750 50  0001 C CNN
 $EndComp
 Text Notes 5100 5300 0    60   ~ 0
 Switching regulators 2A SOT23-5\nTexas instruments TLV62569DBV (2A)\nMicrosemi LX7172 (1.2A)\nDioo microcircuits DIO6015 (1.5A)\nDiodes AP3429/A (2A) - will it meet spec?
+Text Notes 1000 5400 0    60   ~ 0
+SHUTDOWN connected to\nBANK2 on "ram" sheet
 $EndSCHEMATC

ram.bak

@@ -412,6 +412,6 @@ F 4 "www.mouser.com" H 9300 5250 60  0001 C CNN "Distributor1_URL"
 	4    9300 5250
 	1    0    0    -1  
 $EndComp
-Text GLabel 10050 4850 2    60   Input ~ 0
+Text GLabel 8550 3450 0    60   Input ~ 0
 SHUTDOWN
 $EndSCHEMATC

wifi.bak

@@ -225,7 +225,7 @@ Strapping pins\n(avoid using to avoid\nboot problems)\nGPIO0,2,4,5,12,15
 NoConn ~ 7750 5350
 NoConn ~ 7750 5050
 Text Notes 2950 6700 0    60   ~ 0
-ESP32 ADC capable pins\nGPIO36,39,34,35,32,33,25,26,27,\nGPIO14,12,13,15 - shared with HSPI/JTAG\nConnected to "gpio" sheet
+ESP32 ADC capable pins\nGPIO36,39,34,35,32,33,25,26,27,\nGPIO14,12,13,15 - shared with HSPI/JTAG\nConnected to BANK7 on "gpio" sheet
 Text Notes 3850 7350 0    60   ~ 0
 ESP32 HSPI pins\nGPIO12: MISO\nGPIO13: MOSI\nGPIO14: SCK\nGPIO15: SS
 Text Notes 4750 7650 0    60   ~ 0
@@ -308,4 +308,6 @@ Wire Wire Line
 Text Label 5550 4300 0    60   ~ 0
 WIFIEN
 Connection ~ 4750 4300
+Text Notes 1800 5450 0    60   ~ 0
+GPIO12 probably should be held low at reset or disconnected\nother option is to burn flash voltage efuse to 3.3V\nfor GPIO2 and GPIO12 bootstrapping considerations, read\nhttps://github.com/espressif/esp-idf/tree/master/examples/storage/sd_card
 $EndSCHEMATC

wifi.sch

@@ -225,7 +225,7 @@ Strapping pins\n(avoid using to avoid\nboot problems)\nGPIO0,2,4,5,12,15
 NoConn ~ 7750 5350
 NoConn ~ 7750 5050
 Text Notes 2950 6700 0    60   ~ 0
-ESP32 ADC capable pins\nGPIO36,39,34,35,32,33,25,26,27,\nGPIO14,12,13,15 - shared with HSPI/JTAG\nConnected to "gpio" sheet
+ESP32 ADC capable pins\nGPIO36,39,34,35,32,33,25,26,27,\nGPIO14,12,13,15 - shared with HSPI/JTAG\nConnected to BANK7 on "gpio" sheet
 Text Notes 3850 7350 0    60   ~ 0
 ESP32 HSPI pins\nGPIO12: MISO\nGPIO13: MOSI\nGPIO14: SCK\nGPIO15: SS
 Text Notes 4750 7650 0    60   ~ 0
@@ -308,4 +308,6 @@ Wire Wire Line
 Text Label 5550 4300 0    60   ~ 0
 WIFIEN
 Connection ~ 4750 4300
+Text Notes 1800 5450 0    60   ~ 0
+GPIO12 probably should be held low at reset or disconnected\nother option is to burn flash voltage efuse for 3.3V operation\nfor GPIO2 and GPIO12 bootstrapping considerations, read\nhttps://github.com/espressif/esp-idf/tree/master/examples/storage/sd_card
 $EndSCHEMATC