mimxrt: Extend the help() message and README.md.

ports/mimxrt/README.md

@@ -1,17 +1,31 @@
 Port of MicroPython to NXP iMX RT 10xx
 ======================================
 
-Currently supports Teensy 4.0 and the i.MX RT1010 EVK board.
+Currently supports Teensy 4.0, Teensy 4.1, and the
+MIMXRT1010_EVK, MIMXRT1020_EVK, MIMXRT1050_EVK, MIMXRT1060_EVK and
+MIMXRT1064_EVK boards.
 
 Features:
   - REPL over USB VCP
+  - machine.ADC
+  - machine.I2C
+  - machine.LED
   - machine.Pin
+  - machine.PWM
+  - machine.RTC
+  - machine.SDCard
+  - machine.SPI
+  - machine.Signal
+  - machine.SoftI2C
+  - machine.SoftSPI
+  - machine.Timer
+  - machine.UART
+  - LFS2 file system at the internal Flash
+  - SDCard support (not on MIMXRT1010_EVK)
+  - Ethernet (not on Teensy 4.0 and MIMXRT1010_EVK)
 
 Known issues:
-  - pyboard.py doesn't work with files larger than 64 bytes
-  - machine.Pin class currently does not support GPIOMUX option of
-    i.MX RT101x variants
 
 TODO:
-  - Enable TCM
-  - Peripherals (LED, Timers, etc)
+  - More peripherals (Counter, I2S, CAN, etc)
+  - More Python options

ports/mimxrt/main.c

@@ -163,17 +163,25 @@ const char mimxrt_help_text[] =
     "    Pin pull modes are: Pin.PULL_UP, Pin.PULL_UP_47K, Pin.PULL_UP_22K, Pin.PULL_DOWN, Pin.PULL_HOLD\n"
     "  machine.ADC(pin) -- make an analog object from a pin\n"
     "    methods: read_u16()\n"
-    "  machine.UART(id, baudrate=115200) -- create an UART object (id=1 - 8)\n"
+    "  machine.UART(id, baudrate=115200) -- create an UART object (id=1 - 8, board-specific)\n"
     "    methods: init(), write(buf), any()\n"
     "             buf=read(n), readinto(buf), buf=readline()\n"
     "    The RX and TX pins are fixed and board-specific.\n"
-    "  machine.SoftI2C() -- create an Soft I2C object\n"
+    "  machine.SoftI2C() -- create a Soft I2C object\n"
+    "  machine.I2C(id) -- create a HW I2C object\n"
     "    methods: readfrom(addr, buf, stop=True), writeto(addr, buf, stop=True)\n"
     "             readfrom_mem(addr, memaddr, arg), writeto_mem(addr, memaddr, arg)\n"
-    "  machine.SoftSPI(baudrate=1000000) -- create an SPI object ()\n"
+    "    SoftI2C allows to use any pin for sda and scl, HW I2C id's and pins are fixed\n"
+    "  machine.SoftSPI(baudrate=1000000) -- create a Soft SPI object\n"
+    "  machine.SPI(id, baudrate=1000000) -- create a HW SPI object\n"
     "    methods: read(nbytes, write=0x00), write(buf), write_readinto(wr_buf, rd_buf)\n"
+    "    SoftSPI allows to use any pin for SPI, HW SPI id's and pins are fixed\n"
     "  machine.Timer(id, freq, callback) -- create a hardware timer object (id=0,1,2)\n"
     "    eg: machine.Timer(freq=1, callback=lambda t:print(t))\n"
+    "  machine.RTC() -- create a Real Time Clock object\n"
+    "    methods: init(), datetime([dateime_tuple]), now()\n"
+    "  machine.PWM(pin, freq, duty_u16[, kw_opts]) -- create a PWM object\n"
+    "    methods: init(), duty_u16([value]), duty_ns([value]), freq([value])\n"
     "\n"
     "Useful control commands:\n"
     "  CTRL-C -- interrupt a running program\n"