Spark Logic

ATSAM3X8E connection guide

ATSAM3X8E LQFP-144 wiring guide with power, signal assignments, and bench checks.

LQFP-144

144 contacts Current package
LFBGA-144 144 contacts

Microchip Technology · LQFP-144 · Quad flat package · Refer to the mechanical drawing for footprint dimensions.

512 KiB flash in two 256 KiB banks. SRAM: 64 KiB + 32 KiB system banks and 4 KiB NAND controller SRAM.

Power from the on-chip 1.8 V regulator

Required

Use a current-limited 3.3 V supply with the internal regulator enabled. Fit the 10 µH series inductors and the damped branches as in AT03462 §2.1.1. The 1 Ω resistor and 4.7 µF capacitor on each filtered rail are in series to ground.

10 µF minimum at VDDIN, 4.7 µF main branch and local 100 nF bypasses between 3.3 V rail and Ground3.3 V rail10 µF minimum at VDDIN, 4.7 µF main branch and local 100 nF bypassesGround
4.7 µF minimum at VDDOUT and 100 nF per VDDCORE contact between 1.8 V core rail and Ground1.8 V core rail4.7 µF minimum at VDDOUT and 100 nF per VDDCORE contactGround
1 kΩ between Erase strap and GroundErase strap1 kΩGround
6.8 kΩ ±1% between USB bias reference and GroundUSB bias reference6.8 kΩ ±1%Ground
10 pF between USB bias reference and GroundUSB bias reference10 pFGround
100 nF before the USB PHY inductor between 3.3 V rail and Ground3.3 V rail100 nF before the USB PHY inductorGround
100 nF after the inductor between USB PHY filtered rail and GroundUSB PHY filtered rail100 nF after the inductorGround
1 Ω between USB PHY filtered rail and USB PHY damping nodeUSB PHY filtered rail1 ΩUSB PHY damping node
4.7 µF between USB PHY damping node and GroundUSB PHY damping node4.7 µFGround
100 nF before the Analog inductor between 3.3 V rail and Ground3.3 V rail100 nF before the Analog inductorGround
100 nF after the inductor between Analog filtered rail and GroundAnalog filtered rail100 nF after the inductorGround
1 Ω between Analog filtered rail and Analog damping nodeAnalog filtered rail1 ΩAnalog damping node
4.7 µF between Analog damping node and GroundAnalog damping node4.7 µFGround
100 nF before the PLL inductor between 1.8 V core rail and Ground1.8 V core rail100 nF before the PLL inductorGround
100 nF after the inductor between PLL filtered rail and GroundPLL filtered rail100 nF after the inductorGround
1 Ω between PLL filtered rail and PLL damping nodePLL filtered rail1 ΩPLL damping node
4.7 µF between PLL damping node and GroundPLL damping node4.7 µFGround

Bench checks

  • Verify each ground and supply contact against the selected package. Confirm all 3.3 V domains and the 1.8 V core and PLL domains before connecting the debugger.
  • This fixture keeps USB and the ADC disabled. Ground ADVREF and keep ERASE/PC0 low. Leave NRST and NRSTB available for reset inputs as needed.
  • For a working analog reference, backup-mode entry, or USB data, follow the dedicated checklist section and fit its external circuit before enabling that peripheral.

AT03462 §§2.1.1, 2.3–2.5, 2.8–2.9 and 11057C §5

Connection scenarios

Connect the debug serial port

Use a 3.3 V logic-level UART adapter. Cross transmit and receive and share ground. Leave adapter power disconnected from the powered target.

The target TX line goes to adapter RX. The target RX line goes to adapter TX. Both share ground.UART adapterSAM targetRXPA9 · TXTXPA8 · RXGNDGND

Bench checks

  • Enable the debug serial pins and set the UART divider from the actual master clock. Match the terminal’s baud rate and frame settings.
  • Send a known byte and check the actual bit period if the terminal shows corrupted data.

11057C §9.3.1 and UART chapter

LQFP-144 wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

LQFP-144
Top view · Pin 1 at the upper left · Schematic outline Scroll the map to reach all contacts.
Selected pin details

40 · VBG

Reference · Control

USB PHY bias reference. Use the specified 6.8 kΩ and 10 pF network.

11057C · Package pinout and signal descriptions

Electrical limits · Pin in the reference

Models and documents

Includes the 144-lead LQFP and 144-ball LFBGA order codes in 11057C §48. The package power pins differ. GPIO peripheral choices use the SAM3X rows in the PIO tables.

ATSAM3X8E
512 KiB flash in two 256 KiB banks. SRAM: 64 KiB + 32 KiB system banks and 4 KiB NAND controller SRAM.
ATSAM3X8EA-AU
MRL A · 84 MHz Cortex-M3 · industrial temperature −40 to +85 °C.