EvilCrowRF-V2/docs/schematics

Evil Crow RF V2: Hardware Analysis & Pinout Report

(based on: Schematic_EvilCrow_RF_V4_2021-12-14.pdf)

1. Core Architecture

• MCU: ESP32-PICO-D4 (System-in-Package).

  • Dual-core Xtensa LX6, 240MHz.
  • Integrated 4MB SPI Flash.
  • Crystal: 40MHz.

• Programming Interface: USB-to-UART via CH340C (U4).

  • Auto-reset circuit (Q1) uses DTR/RTS to toggle EN/IO0 for automatic flashing.

2. Power Management System

The power analysis in the original PDF contained a component identification error regarding the MOSFET.

• Primary Regulation: BL9110-330BPFB (U6). LDO Regulator providing 3.3V system rail.

• Battery Charging: HP4054 (U5). Linear Li-Ion charger.

  • Charge Current: Configured via R10. Schematic shows options for 500mA or 1A.
  • Charging Status LED (Orange): Connected to U5 STAT pin.

• Battery Monitoring:

  • The voltage divider consists of R14 (100kΩ) and R15 (220kΩ).
  • Topology: GND --- R14(100k) --- GPIO36(VP) --- R15(220k) --- VBAT.
  • Scaling Factor: Ratio as 3.2 ((220+100)/100).
  • Pin: GPIO36 (ADC1_CH0) (Input Only).

• SD Card Power Switching:

  • Component: Q2 (AO3401 P-Channel MOSFET).
  • Function: Controls the VDD_SDIO rail.
  • Logic: Controlled by a GPIO (Net label "CS") to hard-reset the SD card logic by cutting power.

3. Storage Interface (SDIO)

The V4 Schematic utilizes the high-speed SDIO interface, which requires specific GPIOs.

• Mode: 4-bit SDIO.

• Pinout:

  • CLK: GPIO14
  • CMD: GPIO15
  • D0: GPIO2
  • D1: GPIO4
  • D2: GPIO12
  • D3: GPIO13

• Conflict Warning: The config.h attempts to assign RF modules to GPIOs 2, 4, 12, and 13. This is physically impossible on the V4 hardware if the SD card is in use, as these lines are physically wired to the SD slot.

4. RF Module Configuration

The board features three RF modules sharing a common SPI bus but utilizing separate Control/Chip Select lines.

Shared Bus (VSPI)

According to Schematic V4 traces (Net labels SCK2, MISO2, MOSI2):

• SCK: GPIO18
• MISO: GPIO19
• MOSI: GPIO23

Module 1: CC1101 (U2 - 433MHz)

• Function: Sub-GHz Transceiver.
• Chip Select (CS_A): Likely GPIO 5 (based on exclusion, though config.h assigns 5 to SS0, verify strictly as GPIO5 is usually Input Only on some dev boards, but valid output on ESP32 chip).
  • Correction: config.h lists CC1101_SS0 5. However, GPIO 5 is also used for VSPI CS on standard mappings.
• GDO0 / GDO2: Must be mapped to available inputs (e.g., GPIO 34, 35) or free GPIOs (25, 26, 27) if not used by Module 2.

Module 2: CC1101 (U3 - 433MHz)

• Function: Sub-GHz Transceiver (Diversity/RX/TX).
• Chip Select (CS_B): Likely GPIO 27 (matches config.h CC1101_SS1).
• GDO Pins: config.h suggests GPIO 25 and 26, which are free on the schematic.

Module 3: NRF24L01 (U7 - 2.4GHz)

• Function: 2.4GHz ISM (MouseJack/KeyJack).
• Chip Select (CSN): Likely GPIO 15 (per config.h NRF_CSN 15), BUT GPIO 15 is hardwired to SD_CMD in the schematic.
  • Hardware Conflict: If NRF CSN is physically on 15, it conflicts with SD Card operation.

5. User Interface & GPIO Summary

Buttons

• RESET (SW2): Connected to EN (Chip Enable). Hardware reset.
• BOOT (SW1): Connected to GPIO0. Used for flashing mode or user input.
• User Buttons: The config.h defines BUTTON1 34 and BUTTON2 35.
  • Schematic Verification: GPIO 34 and 35 are "Input Only" pins exposed on the header/layout. These match the schematic capabilities.

LEDs

• LED1 (Red): Power Indicator (Always ON via resistor to VCC).

• LED2 (Orange): Charge Indicator (Controlled by U5).

• User LED: config.h defines LED 32. GPIO 32 is available on the ESP32 and likely routed to a discrete LED or header.

6. Corrected GPIO Mapping Table (V4)

Component	Function	GPIO Pin	Note
SD Card	CLK	14	SDIO 4-Bit
SD Card	CMD	15	SDIO 4-Bit
SD Card	D0	2	SDIO 4-Bit
SD Card	D1	4	SDIO 4-Bit
SD Card	D2	12	SDIO 4-Bit
SD Card	D3	13	SDIO 4-Bit
RF Bus	SCK	18	VSPI
RF Bus	MISO	19	VSPI
RF Bus	MOSI	23	VSPI
Battery	Monitor	36	Divider 100k/220k
User	Button 1	34	Input Only
User	Button 2	35	Input Only
User	LED	32	Output
System	UART TX	1	Console
System	UART RX	3	Console

Unassigned / Configurable (RF Control Lines):

• GPIO 5: Likely CC1101 CS (Module A).
• GPIO 27: Likely CC1101 CS (Module B).
• GPIO 25: Available (Likely GDO).
• GPIO 26: Available (Likely GDO).
• GPIO 33: Available.
• GPIO 21: Available.
• GPIO 22: Available.

This analysis is a draft!!! We need willing people to improve it.