Portenta H7 profiles

What the two built-in profiles write to an unprogrammed PF1550 on an Arduino Portenta H7 module, in which order, and when to use each.

Both profiles are tables in pf1550_profiles.hpp, applied in order by ApplyProfile(). They are written for the MC34PF1550A0EP (unprogrammed OTP) on the Portenta H7. On any other board, write your own table (Configuration).

Which one

Profile	Use it when
Default: ApplyPortentaH7DefaultProfile()	You want the order of the Portenta's original firmware; SW1 and SW2 turn off in STANDBY
Carrier: ApplyPortentaH7CarrierProfile()	A carrier board draws +3V3 from the module, or the LDO inputs hang off SW1

Their names for logs are profiles::kPortentaH7DefaultName (portenta_h7_default) and profiles::kPortentaH7CarrierName (portenta_h7_carrier).

The carrier profile differs from the default in three writes:

1. SW1 comes first. SW1_CTRL = 0x0F, then a 5 ms wait, before any LDO register: on the Portenta the LDO inputs are fed from SW1.
2. SW1 stays on in STANDBY. SW1_CTRL = 0x0F instead of 0x01 (on in RUN only).
3. SW2 stays on in STANDBY. SW2_CTRL = 0x0F instead of 0x01, so the carrier's +3V3 survives a STANDBY transition.

Rails on the Portenta H7

Rail use from the Portenta H7 module schematic. The middle column is the set point: the profiles write the LDO voltages, and the bucks run at their OTP values (SW1 and SW2 in the DVS-disabled table).

Rail (schematic)	Set point	Feeds
SW1 (BUCK1, +3V1SW)	3.0 V, OTP code 0x06	USB / ULPI, SDRAM, Ethernet; the LDO inputs
SW2 (BUCK2, +VOUT)	3.3 V, OTP code 0x07	Carrier +3V3, JTAG VTref
SW3 (BUCK3)	3.3 V, OTP code 0x0F (on the modules read so far)	STM32H747, QSPI flash
LDO1	1.0 V, code 0x05	MIPI bridge
LDO2	1.8 V, code 0x00	MIPI, USB / ULPI
LDO3	1.2 V, code 0x09	STM32 DSI, Ethernet PHY

No buck voltage writes

Neither profile writes SWx_VOLT, SWx_STBY_VOLT or SWx_SLP_VOLT. SW3's are read-only (no DVS), and so are SW1's and SW2's with DVS disabled, which is the case for 3.0 V and 3.3 V set points; on a DVS-enabled buck the Portenta firmware's codes would have meant 0.6875 V. Read the snapshot to see the OTP set points. On a part whose SW1 or SW2 has DVS, set the voltage with SetSwVoltageMv() after the profile.

The carrier profile, write by write

The writes, in table order:

Register	Value	Effect
SW1_CTRL (0x35)	0x0F	On in RUN, STANDBY, SLEEP, low power; then wait 5 ms
LDO2_VOLT (0x4F)	0x00	1.8 V
LDO1_VOLT (0x4C)	0x05	1.0 V
LDO1_CTRL (0x4D)	0x0F	On in every mode, low power
LDO3_VOLT (0x52)	0x09	1.2 V
LDO3_CTRL (0x53)	0x0F	On in every mode, low power
PWRCTRL0 (0x58)	0x03	STANDBYDLY = 3, STANDBYINV = 0: STANDBY high means standby
LED_PWM (0x9C)	0x80	LED enabled at 0/32 duty; wait 1 ms
LED_CNFG (0x9E)	0x20	LEDOVRD: software owns the LED, so it stays off; wait 1 ms
SW3_CTRL1 (0x42)	0x02	SW3 current limit 1.5 A typical; wait 1 ms
VBUS_INLIM_CNFG (0x94)	0xA0	VBUS input limit 1500 mA
SW2_CTRL (0x3B)	0x0F	On in every mode, low power
SW3_CTRL (0x41)	0x0F	On in every mode, low power
LDO2_CTRL (0x50)	0x0F	LDO2 on; always the last write

LDO2_CTRL is last in both profiles. That order comes from the Portenta's original start-up code, and earlier bring-up notes report I2C trouble when it was written sooner; the data sheet gives no ordering rule for it.

Strap pins

Signal (STM32H747 pin)	Normal level	Driver call
PMIC STANDBY (PJ0)	Low: RUN	SetPowerMode(PowerMode::Run)
USB_VBUS_EN (PJ4)	High	SetUsbRails(true, ...)
USB_OTG_EN (PJ6)	High	SetUsbRails(..., true)
PMIC INT (PK0)	Input	Read by your code

The PF1550 sits on I2C1 (PB6 SCL, PB7 SDA) at 0x08.

When to apply

Apply the profile early, after the strap pins and before USB or Ethernet start. The PF1550 keeps its registers across an MCU reset, so a profile that was applied once stays in force until the PMIC is powered down; after changing a profile, power the module down completely (USB and battery off) before you judge the result.

Next: API guide.