ESP32 ROM console¶
When an ESP32 is unable to boot from flash ROM (and the fuse disabling it hasn’t been blown), it boots into a rom console. The console is based on TinyBasic, and statements entered should be in the form of BASIC statements. As is common in the BASIC language, without a preceeding line number, commands entered are executed immediately; lines with a prefixed line number are stored as part of a program.
Full list of supported statements and functions¶
System¶
BYE - exits Basic, reboots and retries booting from flash
END - stops execution from the program, also “STOP”
MEM - displays memory usage statistics
NEW - clears the current program
RUN - executes the current program
IO, Documentation¶
PEEK( address ) - get a 32-bit value from a memory address
POKE - write a 32-bit value to memory
USR(addr, arg1, ..) - Execute a machine language function
PRINT expression - print out the expression, also “?”
PHEX expression - print expression as a hex number
REM stuff - remark/comment, also “’”
Expressions, Math¶
A=V, LET A=V - assign value to a variable
+, -, *, / - Math
<,<=,=,<>,!=,>=,> - Comparisons
ABS( expression ) - returns the absolute value of the expression
RSEED( v ) - sets the random seed to v
RND( m ) - returns a random number from 0 to m
A=1234 - * Assign a decimal value*
A=&h1A2 - * Assign a hex value*
A=&b1001 - Assign a binary value
Control¶
IF expression statement - perform statement if expression is true
FOR variable = start TO end - start for block
FOR variable = start TO end STEP value - start for block with step
NEXT - end of for block
GOTO linenumber - continue execution at this line number
GOSUB linenumber - call a subroutine at this line number
RETURN - return from a subroutine
DELAY - Delay a given number of milliseconds
Pin IO¶
IODIR - Set a GPIO-pin as an output (1) or input (0)
IOSET - Set a GPIO-pin, configured as output, to high (1) or low (0)
IOGET - Get the value of a GPIO-pin
Example programs¶
Here are a few example commands and programs to get you started…
Read UART_DATE register of uart0¶
> PHEX PEEK(&h3FF40078)
15122500
Set GPIO2 using memory writes to GPIO_OUT_REG¶
Note: you can do this easier with the IOSET command
> POKE &h3FF44004,PEEK(&h3FF44004) OR &b100
Get value of GPIO0¶
> IODIR 0,0
> PRINT IOGET(0)
0
Blink LED¶
Hook up an LED between GPIO2 and ground. When running the program, the LED should blink 10 times.
10 IODIR 2,1
20 FOR A=1 TO 10
30 IOSET 2,1
40 DELAY 250
50 IOSET 2,0
60 DELAY 250
70 NEXT A
RUN
Credits¶
The ROM console is based on “TinyBasicPlus” by Mike Field and Scott Lawrence, which is based on “68000 TinyBasic” by Gordon Brandly