Add ESP32-H2 and the ESP32-H2-DevKitM-1 board

[zombieleet]

This PR adds the ESP32-H2 chip and the Espressif ESP32-H2-DevKitM-1 board.

The ESP32-H2 is close to the ESP32-C6

The ESP32-H2 is not very different from the ESP32-C6. Both chips use the same RISC-V core, the same PLIC interrupt controller, the same PCR clock and reset block, the same interrupt matrix, the same USB Serial/JTAG block and the same memory map. So this port uses the existing ESP32-C6 code where it can:

• The ESP32-C6 startup assembly (src/device/esp/esp32c6.S). The H2 ROM has the same cache functions, at different addresses.
• The shared PLIC and timer interrupt code (runtime_esp32xx_plic.go, added in runtime/esp32: prepare the shared runtime for more RISC-V chips #5749).
• The ESP32-C6 interrupt dispatcher (interrupt_esp32c6.go) and USB Serial/JTAG driver (machine_esp32c6_usb.go), with a build tag.

machine_esp32h2.go started as a copy of machine_esp32c6.go. It changes only the parts in the table below.

Item	ESP32-C6	ESP32-H2 (this PR)
CPU clock	160 MHz from PLL	32 MHz from XTAL (96 MHz PLL in a later PR)
Crystal	40 MHz	32 MHz
HP SRAM	512 KB	320 KB
ROM cache function addresses	C6 values	H2 values (esp32h2.rom.ld)
TIMG0 tick	PLL_F80M / 2, 25 ns	XTAL / 4, 125 ns
TIMG clock select values	0 XTAL, 1 PLL_F80M, 2 RC_FAST	0 XTAL, 1 RC_FAST, 2 PLL_F48M
UART clock	FOSC 80 MHz	XTAL 32 MHz (PCR SCLK_SEL 3)
UART CLK_CONF fields	SCLK_SEL, SCLK_DIV_* in the UART block	In PCR. The UART block has TX_SCLK_EN and SCLK_EN only
UART CPU interrupt	7	13 (see notes)
GPIO	GPIO0 to GPIO30	GPIO0 to GPIO27
Image chip ID	0x000d	0x0010
Flash clock code	80 MHz = 0x0	48 MHz = 0xF

Commits

1. builder: add the esp32h2 firmware image format. Chip ID 0x0010 and flash code 0xF (48 MHz, the H2 maximum), from esptool targets/esp32h2.py.
2. runtime,machine,targets: add ESP32-H2 support. The esp32h2 chip target, the linker script, the H2 clock setup, the machine package and the build tags on the shared files.
3. machine,targets: add the ESP32-H2-DevKitM-1 board. The board uses the port printed UART (a CP2102N on UART0), so it uses esp32flash and serial: uart. The onboard LED is a WS2812 on GPIO8, so the board file defines WS2812 and BUTTON (GPIO9) but not LED, the same as other boards with only an addressable LED. The smoke test builds examples/machinetest and examples/serial.

Tested on an ESP32-H2-DevKitM-1 (N4)

Test	Result
Flash with esp32flash on the UART port	Pass
examples/serial	Pass, lines 1.000 s apart
examples/echo (UART RX interrupt)	Pass
GPIO output (external LED on GPIO10)	Pass
GPIO input with pull-up and pull-down	Pass
Pin-change interrupt (BOOT button)	Pass
USB Serial/JTAG port	Builds, not tested

make smoketest-esp passes. The ESP32-C6 binaries do not change with this PR.

[zombieleet]

IMG_4473.mov

IMG_4472.mov

[deadprogram]

@zombieleet please rebase this PR against dev now that #5749 has been merged. You can try a stacked PR next time, perhaps? Thanks.

[zombieleet]

@zombieleet please rebase this PR against dev now that #5749 has been merged. You can try a stacked PR next time, perhaps? Thanks.

Yah, I actually wanted to do that, but stacked pr only works on branches that are in the tinygo repo itself

[zombieleet]

@deadprogram rebased. Thanks

[deadprogram]

Thanks for the rebase and for this port @zombieleet. The following is edited from an automated review:

1. targets/esp32h2.ld adds the .rodata alignment line and the two ASSERT checks, but targets/esp32c6.ld does not have them. Does the C6 have the same latent issue? Perhaps add them to the C6 script too, here or in a follow-up.

2. esp32c6.S, interrupt_esp32c6.go and machine_esp32c6_usb.go are now shared with the H2 but still carry the C6 name. Should you rename them in a later PR so it is clear they cover both chips? Seems like a good idea maybe?

[deadprogram]

@zombieleet please see #5755 for some C6 fixes discovered while testing this PR.

[deadprogram]

Thanks again @zombieleet for working on this. I addressed one of my comments in a new PR, and the other one can wait for a future moment. Now merging.