ESP32-VGA

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Tindie-mediums.png

ESP32-VGA P923-72PX.jpg

Contents

Features

  • ESP32 Module
  • 6-bit VGA color
    • 2:2:2 R:G:B
  • 2 x PS-2 DIN connectors
    • 5V mouse/keyboard
    • 3.3V to 5V level shifters
      • Better than 5V keyboard with series resistors
    • 10K pull-ups on both sides
  • 2 x FTDI connectors
  • 5V DC Jack
  • 3.3V regulator (optional)
  • GVS pins for extra ESP32 pins
  • 95x95mm form factor
  • 6-32 mounting holes

ESP-32 Module

ESP32 MODULE-720PX.jpg

ESP-32 Module Pinout

ESP32-Pinout.jpg

"Chip" on the module

Esp32-pinout-chip-ESP-WROOM-32.png

ESP32 Pin Usage - Rev 1

ESP-32 VGA Pinout.PNG

ESP32 Pin Usage - Rev 2

ESP-32 VGA Pinout Rev2.PNG

Module Features

  • Architecture: Xtensa Dual-Core 32-bit LX6
  • CPU frequency: up to 240MHz
  • Total RAM available: 528KB (part of it reserved for system)
  • BootROM: 448KB
  • Internal FlashROM: none
  • External FlashROM: code and data, via SPI Flash; usual size 4MB
  • GPIO: 34 (GPIOs are multiplexed with other functions, including external FlashROM, UART, etc.)
  • UART: 3 RX/TX UART (no hardware handshaking), one TX-only UART
  • SPI: 4 SPI interfaces (one used for FlashROM)
  • I2C: 2 I2C (bitbang implementation available on any pins)
  • I2S: 2
  • ADC: 12-bit SAR ADC up to 18 channels
  • DAC: 2 8-bit DACs
  • RMT: 8 channels allowing accurate pulse transmit/receive
  • Programming: using BootROM bootloader from UART - due to external FlashROM and always-available BootROM bootloader, the ESP32 is not brickable

Video DAC LTSpice Simulation

Summing Resistor DAC

  • 5% resistors are "good enough"
  • 1V into 75 Ohm VGA load
  • 3.3V drive
  • ESP32 has 40 mA drive
    • Uses 10 mA (max)
    • R4 = 1.2 mA to -10 mA
    • R3 = 1.1 mA to -5.3 mA
  • Output in 4 steps
    • 0V
    • 0.3V
    • 0.65V
    • 0.96V

VGA Sim 2R.PNG

Headers (Rev 1 board)

H1 - 3.3V SRC select

H1 3p3V Select.png

  • 1-2 = Get 3.3V from ESP32 on-board regulator
  • 2-3 = Get 3.3V from on-board regulator (Default)

H2 - 5V SRC Select Jumper (Rev 1 Board)

  • 5V power options for the 5V to 3.3V regulator

H2 5V Select.png

  • 2x4 header
  • Care must be taken to install the correct jumpers
  • USB jumper sends out 5V when a USB cable is connected to the ESP32 module

Power from DC Jack

  • Do not connect USB cable when the DC jack is used
  • 1-2 = VUSB - Install - Power to ESP32
  • 3-4 = DCIN - Install - Power comes from DC jack
  • 5-6 = FTDI5V_1 - Do not install
  • 7-8 = FTDI5V_2 - Do not install

Power from USB on ESP32 module

  • 1-2 = VUSB - Install - 5V comes from USB on ESP32 module
  • 3-4 = DCIN - Do not install
  • 5-6 = FTDI5V_1 - Do not install
  • 7-8 = FTDI5V_2 - Do not install

Power from FTDI #1 (Rev 1)

  • Do not use this position with "most" FTDI cards since they will drive 5V on the Rx/Tx pins

Power from FTDI #2

  • Do not use this position with "most" FTDI cards since they will drive 5V on the Rx/Tx pins

Connectors (Rev 1 board)

P2/P4 = GVS - Rev 1

  • Ground/Voltage/Signal lines
  1. GPIO13
  2. GPIO14
  3. GPIO16
  4. GPIO17
  5. GPIO35
  6. GPIO34
  7. VN
  8. VP

P3 - VGA - Rev 1

  • ESP32 pins
  HSync => GPIO23
  VSync => GPIO15
  R0    => GPIO22
  R1    => GPIO21
  G0    => GPIO19
  G1    => GPIO18
  B0    => GPIO5
  B1    => GPIO4

J2 - FTDI #1 - Rev 1

  1. GND
  2. RTS (Not used)
  3. 5V (Power in if H2 is configured)
  4. RX (from card to External FTDI)
  5. TX (from External FTDI to card)
  6. CTS (Not used)

Connect to FTDI card - Rev 1

  • Set FTDI jumper to 3.3V (unlike picture below)
  • Cross-over pins 4 and 5 when connecting to FTDI card (Rev 1 only)

FTDI rot.jpg

J6 - FTDI #2 - Rev 1

  • Rev 1 board won't program or boot with FDTI #2 card attached
  • This interface is in common with the USB-to-Serial interface on the ESP32 module
  1. GND
  2. RTS (Not used)
  3. 5V (Power in if H2 is configured)
  4. RX (from card to External FTDI)
  5. TX (from External FTDI to card)
  6. CTS (Not used)

Connect to FTDI card - Rev 1

  • Set FTDI jumper to 3.3V
  • Cross-over pins 4 and 5 when connecting to FTDI card (Rev 1 only)

FTDI rot.jpg

J3 - PS/2 Keyboard - Rev 1

  • Purple DIN 6 connector
  • ESP32 pins
  DAT   => 32
  CLK   => 33

J4 - PS/2 Mouse - Rev 1

  • DIN 6 connector
  • ESP32 pins
  DAT   => 27
  CLK   => 26

J5 - Audio Out - RCA Jack - Rev 1

  • ESP32 pins
  AUD   => 25

J6 - UART2 - Rev 1

  • Most recent (2020-02) ANSI terminal uses pin 34
  RX    => 12
  TX    => 2

J15 - 5mm Terminal Block - Rev 1

  • 5V
  • Gnd

Headers (Rev 2 board)

H1 - 5V - Rev 2

  • Power board from either the DC Jack or ESP32 USB power
  • Do not power from 5V Power jack and connect USB cable to the ESP32 module at the same time
    • ESP32 module has blocking diode to protect the module

H2/H3 - GVS - Rev 2

  • 3x4 header
  • Ground/Voltage/Signal lines
  1. GPIO35
  2. GPIO12
  3. VN/I39
  4. VP/I36

Connectors (Rev 2 board)

P1 - PS/2 Mouse - Rev 2

  • DIN 6 connector
  • ESP32 pins
  DAT   => GPIO27
  CLK   => GPIO26

P2 - PS/2 Keyboard - Rev 2

  • Purple DIN 6 connector
  • ESP32 pins
  DAT   => GPIO32
  CLK   => GPIO33

P3 - VGA - Rev 2

  • ESP32 pins
  HSync => GPIO23
  VSync => GPIO15
  R0    => GPIO22
  R1    => GPIO21
  G0    => GPIO19
  G1    => GPIO18
  B0    => GPIO5
  B1    => GPIO4

P4 - Audio Out - RCA Jack - Rev 2

  • ESP32 pins
  AUD   => GPIO25

J1 - 5V Power - Rev 2

  • Center +5V

J2 - FTDI #1 - Rev 2

  • This interface is in common with the USB-to-Serial interface on the ESP32 module
  1. GND
  2. RTS (Not used)
  3. 5V (Not used)
  4. RX (from card to External FTDI)
  5. TX (from External FTDI to card)
  6. CTS (Not used)
  • Most recent (2020-02) ANSI terminal uses pin 34
  RX    => GPIO3
  TX    => GPIO1

Connect to FTDI card - Rev 2

  • Set FTDI jumper to 3.3V

FTDI rot.jpg

J3 - FTDI #2 - Rev 2

  1. GND
  2. RTS (Not used)
  3. 5V (Power in if H2 is configured)
  4. RX (from card to External FTDI)
  5. TX (from External FTDI to card)
  6. CTS (Not used)
  RX    => GPIO34
  TX    => GPIO2

Connect to FTDI card - Rev 2

  • Set FTDI jumper to 3.3V
  • Cross-over pins 4 and 5 when connecting to FTDI card (Rev 1 only)

FTDI rot.jpg

J4 - SD Card - Rev 2

  • Brought to GVS header pins (Rev 1)
  • Brought to SD Card (Rev 2)
  MOSI  => GPIO17
  MISO  => GPIO16
  CLK   => GPIO14
  CS    => GPIO13

VGA - Ideal Drive 2:2:2 Case

  • Ideal case drive current
    • 0.7V into 75 Ohms = 9.33 mA
    • ESP32 has a 3.3V driver which can drive more than 10 mA
    • 1% resistors
      • Get closest values
      • R-2R values
    • Ideal resistor values are 417.9/835.7 ohms
    • 1% standard values are 422, 845 Ohms
      • 0V, 0.228V, 0.460V, 0.693V
  • Voltage steps are:

VGA Sim 2R Voltage.PNG

  • Current steps are:

VGA Sim 2R Current.PNG

FabGL GPIOs assignment summary - fabgl dev board rev2

From here


I2C (not usable with VGA)

  SDA   => GPIO4  (conflicts with VGA B1)
  SCL   => GPIO15 (conflicts with VGA VSync)

SPI Display - VSPI (not usable with VGA)

  CLK   => GPIO18 (conflicts with VGA G1)
  MISO  => GPIO19 (conflicts with VGA G0)
  MOSI  => GPIO23 (conflicts with VGA HSync)
  CS    => GPIO5  (conflicts with VGA B0)
  D/C   => GPIO22 (conflicts with VGA R0)
  RESET => GPIO21 (conflicts with VGA R1)

Software

Arduino Programming

  • Board : "DOIT ESP32 DEVKIT V1"

Ardino ESP32.png

FabGL

  • Display Controller features/applications
    • VGA
    • SSD1306
    • PS/2 Mouse and Keyboard Controller
    • Graphics Library
    • Sound Engine
    • Game Engine
    • ANSI/VT Terminal for the ESP32

FabGL Libraries

FabGL Arduino library

Installing the released library

FabGL Library.PNG

Using Latest FabGL builds

Here's how I did it

  1. Install drivers via Arduino from the Library Manager. These are not the latest files. Space Invaders should run but not have sound (as of now because it's the older version).
  2. Move the FabGL from the Arduino libraries file folder to the desktop.
  3. Copy the FabGL from the GitHub download to the Arduino files folder (where you removed the other folder).
  4. Examples will now be the latest.
  5. Compile/download/test the new files. You know it works if you now get sound from Space Invaders.
  6. Save as where you would normally save your Arduino sketches.

MicroPython

ESP-IDF

Operating Systems

Schematic

Rev 2 Changes

ESP32-VGA CAD REV2-bw.PNG

  • Rev 1 board won't program or boot with FDTI #2 card attached
  • Swap FTDI pins 4 and 5 (J2 and J6)
    • Allow direct connect to FTDI card (no swap)
  • Move FTDI Rx line (GPIO12 to GPIO34)
    • Earlier FabGL had previos connection
  • Add SD Card connector
    • MISO => GPIO 16
    • MOSI => GPIO 17
    • CLK => GPIO 14
    • CS => GPIO 13
    • Remove I/O pins from GVS connector
  • Replace H1/H2 with 1x2 to select/remove DC jack power
  • Change ESP32 silkscreen
    • SD card
  • VGA High/Low lines backwards on silkscreen

Prototype

FabGL P905-512pxV.jpg

Assembly Sheet

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