usb-esp-programmer-isolated

Pinout — Isolated USB-C ESP Programmer (HC22003)

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Isolated target header (programmer → target):

Signal	Direction	Connect to ESP
GND (isolated)	—	target GND
VCC (isolated)	out (optional)	3V3 — only if powering the target
TX	out	target RX
RX	in	target TX
EN (RST)	out	EN / reset
IO0 (BOOT)	out	IO0 / boot strap

• Logic level: 3.3 V. Cross TX↔RX.
• The whole target side sits behind the isolation barrier — keep your target ground separate from PC/USB ground to preserve isolation.

Pull-up jumpers (JP1 / JP2)

Next to the target header are two small 2-pin jumpers. Each connects an optional pull-up (referenced to the isolated side) onto one of the ESP’s two strapping pins:

Jumper	Pull-up on	ESP pin
JP1	EN / RESET	chip-enable
JP2	IO0 / BOOT	boot strap

• Jumper cap fitted = pull-up ON (referenced to the programmer’s isolated side).
• Ships with the caps removed (pull-ups OFF) — the default for the isolated version.

Why off by default. On the isolated programmer a fitted cap ties the target’s strap pin to the programmer’s isolated side. Isolation-critical, independently-powered, or mains-referenced targets should stay referenced to their own supply and ground, so the caps are left off out of the box.

Fit a cap when you’re flashing a bare module powered from the programmer’s isolated VCC that needs EN/IO0 held high to boot. Fit JP1 (EN), JP2 (IO0), or both as needed. Keep them off for any target that has its own supply or its own pull-ups.

(JP1/JP2 are marked on the board silkscreen. Isolation voltage rating and electrical limits: see the product page.)

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