v1.4.2A

Fix 5mm terminal in BOM

Same part was on two lines in BOM, combine / fix in source and regenerate.

v1.4

V1.3 was never released, only used for internal prototypes - so this changelog includes the V1.3 and V1.4 changes, so that they may be referred to in one place.

• Board shrunk from 140mm width to 135mm (restored to original RUMBA dimensions)
  • Maintains previous mounting layout (same as original RUMBA)
• Power Connector Overhaul
  • Swap to higher-quality screw terminals with better ratings
    • 15A -> 20A Max. Current
    • 12-20AWG -> 10-20AWG
• USB Overhaul
  • miniUSB replaced with microUSB
    • Attaches more securely to board, harder to damage
    • Latching connector harder to accidentally knock out
    • More common cables
  • ESD protection IC added to USB input
    • Replaces discrete TVS diodes
    • Offers better protection of D+ and D- lines from ESD damage
    • Also offers protection to power/ground rail, which TVS diodes did not
  • Shield added to USB pin header, allows for direct connection of 5-pin USB panel-mount sockets
• 5V selection jumper replaced with automatic OR-ing diodes
  • No longer any need for user to specify USB or DCDC as 5V source via jumper
  • Board will work from either source
  • Defaults to DCDC when both are present
• Replace large crystal oscillators with more compact SMD package
  • Takes up less board space + improves board routing
• Overhauled 12V regulator
  • Newer, more efficient regulator (AOZ1284 replaces LM2596)
    • Regulator current-rating improved from 3A -> 4A
    • Switching frequency increased from 150kHz to 500kHz (allows smaller inductor / higher inductor current-rating)
  • New diode + inductor selected for higher current capability (testing confirms maximum continuous current draw of 2.5A, limited by inductor temperature)
  • Now capable of running up to 12V 30W heater, or 12V fans, etc
  • More compact layout
• Easier troubleshooting
  • Indicator LEDs added to USB, 5V_DCDC, 5V, 12V
• Improve board routing
  • Routing of high-current traces and pours near power input and heated bed section have been improved
  • Microcontroller oscillator circuits re-routed and tidied
  • Microcontroller reset circuits re-routed and tidied
  • Routing of all stepper-related signals tidied

v1.2

Improvements:

• Improve 5V Regulator
  • Change inductor L3 to smaller part with higher current rating
  • Change diode D5 to smaller part with higher current rating + simpler footprint
  • Improve routing + polygon pours around 5V regulator to improve thermal conductivity to ground plane
• Improve 12V Regulator
  • Change inductor L4 to smaller part with higher current rating
  • Change diode D8 to smaller part with higher current rating

v1.1

Improvements:

• Change 5V regulator from LT1933 to AOZ1282.
  • Higher peak efficiency (95% vs 87%)
  • Higher maximum output current (1.2A vs 0.6A)
• Thicken traces / pours relating to heated bed output
• Increase spacing around ISP2 and EXP3 headers for easier access
• Change stepper motor wire labels to match more common cable colours
• Change stepper driver micro-stepping DIP-switch orientations to be more intuitive

Fixes:

• Correct DTR pin for USB comms on ATmega16U2
• Update all screw holes to be uniform, previously were slightly differing sizes
• Correct D8 footprint to correct footprint for MURS320 as per BOM

v1.0

Changes from original RUMBA design:

• Replace PTC fuses with replaceable automotive mini blade fuses
  • Quicker response in event of short / reverse-voltage
  • Allows > 16V on bed circuit, unlike old design (now full 24V compatibility)
• Change MOSFETs from PSMN7R0-60YS to PSMN1R8-40YLC
  • PSMN7R0-60YS is not logic-level compatible, RDSon at 4.5V is not defined
  • PSMN1R8-40YLC has much lower RDSon and is logic-level compatible
• Add flyback diodes to each MOSFET-driven output
• Correct LCD connector labelling
• Add 4 x I2C headers for expansion
• Redo placement and routing of decoupling capacitors
• Increase board size to 140x75mm