Hardware

This page contains information about the hardware features of the 121GW.

Main Processor

• STM32L152ZDT6 ARM Cortex-M3, LQFP144 package, Category 4
• 48KB RAM, 384KB ROM (the first 24KB is used by the bootloader, rest should be available for user code, 1.02 firmware is 116KB), 12KB EEPROM
• 4MHz crystal, xx MHz (will prob need to know option bytes and read code more to get this. also it gets switched during SD access in log_try_flush_samples_from_eeprom())

Measurement Frontend

• Hycon HY3131 multimeter frontend
  • 4.9152MHz crystal, used as frequency reference. Can be calibrated in software.
• AD8436 true RMS chip
• MAX4238 low offset operational amplifier
  • x10 gain on amperage measurement for low burden voltage

Additional

• RTC: NJU6350R
  • 32.768KHz watch crystal
  • CR1220 backup battery
• Bluetooth: BLE112 module