Hello,

I get a panic error when trying to initialize UART port, with ESP32-spiram firmware.

I have tried with the stable V1.12 and the latest:

`[quote]MicroPython v1.12-553-gc521c178e on 2020-06-18; ESP32 module (spiram) with ESP32
Type "help()" for more information.

from machine import UART, PIn
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: can't import name PIn
from machine import UART, Pin
uart=UART(2, 9600)

Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.
Core 1 register dump:
PC : 0x400dfb48 PS : 0x00060d30 A0 : 0x800d2dc9 A1 : 0x3ffce8b0
A2 : 0x3f8177c0 A3 : 0x000000b1 A4 : 0x3ffce8d0 A5 : 0xff1d0000
A6 : 0x00000001 A7 : 0x000000ff A8 : 0x00000019 A9 : 0x3ffce890
A10 : 0xff1d0000 A11 : 0x00000001 A12 : 0x00000001 A13 : 0x3ffc2338
A14 : 0x00000003 A15 : 0x3ffce990 SAR : 0x00000000 EXCCAUSE: 0x0000001c
EXCVADDR: 0xff1d001c LBEG : 0x400d2fe0 LEND : 0x400d3038 LCOUNT : 0x00000000

ELF file SHA256: 0000000000000000000000000000000000000000000000000000000000000000

Backtrace: 0x400dfb48:0x3ffce8b0 0x400d2dc6:0x3ffce8d0 0x400f74ec:0x3ffce910 0x400d303b:0x3ffce930 0x400d3364:0x3ffce950 0x400d2974:0x3ffce970 0x400d621d:0x3ffce990 0x400d62e1:0x3ffce9b0 0x400d6c09:0x3ffce9d0 0x4010741e:0x3ffcea50 0x40107531:0x3ffceae0 0x400f739d:0x3ffceb10 0x4009571e:0x3ffceb40

Rebooting...
ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:5008
ho 0 tail 12 room 4
load:0x40078000,len:11608
ho 0 tail 12 room 4
load:0x40080400,len:6120
entry 0x400806bc
I (615) psram: This chip is ESP32-D0WD
I (615) spiram: Found 64MBit SPI RAM device
I (615) spiram: SPI RAM mode: flash 40m sram 40m
I (618) spiram: PSRAM initialized, cache is in low/high (2-core) mode.
I (625) cpu_start: Pro cpu up.
I (629) cpu_start: Application information:
I (634) cpu_start: Compile time: Jun 18 2020 00:56:09
I (640) cpu_start: ELF file SHA256: 0000000000000000...
I (646) cpu_start: ESP-IDF: v3.3.2
I (651) cpu_start: Starting app cpu, entry point is 0x40083574
I (641) cpu_start: App cpu up.
I (1526) spiram: SPI SRAM memory test OK
I (1527) heap_init: Initializing. RAM available for dynamic allocation:
I (1527) heap_init: At 3FFAFF10 len 000000F0 (0 KiB): DRAM
I (1533) heap_init: At 3FFB6388 len 00001C78 (7 KiB): DRAM
I (1539) heap_init: At 3FFB9A20 len 00004108 (16 KiB): DRAM
I (1546) heap_init: At 3FFBDB5C len 00000004 (0 KiB): DRAM
I (1552) heap_init: At 3FFCABA8 len 00015458 (85 KiB): DRAM
I (1558) heap_init: At 3FFE0440 len 00003AE0 (14 KiB): D/IRAM
I (1564) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (1571) heap_init: At 4009A528 len 00005AD8 (22 KiB): IRAM
I (1577) cpu_start: Pro cpu start user code
I (254) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
MicroPython v1.12-553-gc521c178e on 2020-06-18; ESP32 module (spiram) with ESP32
Type "help()" for more information.[/quote]`

The error can rise immediately or after some delay.