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Frontmatter
{
"title": "TinyDuino Hardware Architecture",
"created": "2026-11-03T11:50:00Z",
"updated": "2026-11-03T11:50:00Z",
"slug": "hardware-architecture"
}TinyDuino Modular Hardware Architecture
The TinyDuino LightMeter workbench is constructed from a miniature 20mm × 20mm modular stack manufactured by TinyCircuits. Follow the official TinyDuino Setup Tutorial and consult the TinyShield Compatibility Matrix for bus pin assignments. Unlike monolithic development boards, TinyDuino breaks the microcontroller, USB programming bridge, wireless communications, and prototyping circuits into separable shield layers connected by a proprietary 30-pin stackable header.
graph TD
A["Layer 4 (Top): Proto Board TinyShield (ASD2009 Rev 1)<br/>KY-018 LDR Module + Signal Wiring"] --> B["Layer 3: Bluetooth LE TinyShield (ASD2112 Rev 2)<br/>Bluegiga BLE112 Smart Module (BGAPI)"]
B --> C["Layer 2: USB TinyShield (ASD2101 Rev 6)<br/>FTDI FT231X UART Programmer (DTR Reset)"]
C --> D["Layer 1 (Bottom): TinyDuino Processor Board (ASM2001 Rev 9)<br/>ATmega328P @ 8 MHz, 3.3V System Logic"]
Component Specifications
1. TinyDuino Processor Board (ASM2001 Rev 9)
- Microcontroller: Microchip ATmega328P (8-bit AVR RISC architecture)
- Clock Speed: 8 MHz internal calibrated / external ceramic resonator
- Operating Voltage: 3.3V regulated logic (3.0V – 5.5V supply tolerance)
- Flash Memory: 32 KB (with 2 KB used by the Optiboot bootloader)
- SRAM: 2 KB (2048 bytes dynamic heap and stack)
- EEPROM: 1 KB (1024 bytes non-volatile parameter storage)
- Power Rail: Low-dropout linear regulator providing clean 3.3V power to the stack bus (
VCC).
2. Bluetooth Low Energy TinyShield (ASD2112 Rev 2)
- Wireless Module: Silicon Labs / Bluegiga BLE112 (Texas Instruments CC2540 core)
- Bluetooth Specification: Bluetooth Smart / Bluetooth 4.0 Single Mode Low Energy
- Firmware:
BGLib_U1A1P_38400_noflow(38,400 baud UART, no hardware flow control) - Host Communication Pins:
Pin 3(Arduino RX) ➔ Bluegiga TXPin 4(Arduino TX) ➔ Bluegiga RX
- Radio Characteristics: Built-in ceramic chip antenna, +3 dBm TX power, -93 dBm RX sensitivity.
3. USB & ICP TinyShield (ASD2101 Rev 6)
- USB Controller: FTDI FT231X USB-to-UART serial interface
- Auto-Reset Circuitry: Capacitive coupling from
DTRto the ATmega328PRESETpin to trigger Optiboot during firmware flashing viaarduino-cli. - Serial Speed: 115,200 baud for host diagnostics and programming.
4. Proto Board TinyShield (ASD2009 Rev 1)
- Grid Layout: 0.1" (2.54mm) pitch through-hole prototyping matrix bringing out all 30 pins of the TinyDuino bus.
- Circuit Population: Host for the KY-018 photoresistor module, pull-up resistors, and optional status LEDs.
30-Pin TinyShield Bus Pinout
| Pin Range | Function | Notes |
|---|---|---|
Pin 0, 1 | RXD, TXD | Hardware Serial 0 wired to USB shield for flashing & logging |
Pin 3, 4 | BLE_TX, BLE_RX | SoftwareSerial connection to BLE112 module at 38,400 baud |
Pin 7 | AUX_LED | Auxiliary LED output for nightlight & status blinking |
Pin 13 | LED_BUILTIN | Onboard status indicator LED |
Pin A0 | LIGHT_ANALOG | 10-bit analog input for KY-018 voltage divider |
Pin A4, A5 | SDA, SCL | Hardware I2C bus reserved for auxiliary environmental sensors |
VCC | 3.3V Rail | Regulated system logic voltage reference |
GND | Ground | System common ground (0 V) |