not used.
[](https://registry.platformio.org/libraries/robtillaart/MultiSpeedI2CScanner)
MultiSpeedI2CScanner is a menu driven I2C scanner, see below. The scanner is tested on an UNO and an ESP32.
The scanner provides an overview of which addresses can be found at which speed. This allows one to optimize the I2C performance of many devices above the standard 100KHz speed.
Since version 0.2.0 the MultiSpeed I2C Scanner has a time out of default 25 milliseconds on the I2C transactions. This feature prevents locking of the I2C scanner and is large enough even for low I2C speeds.
Not all platforms support the I2C timeout, so it is implemented conditional.
Set the value of I2C_TIMEOUT to zero to disable it. Note this is not a menu option and must be done compile time (for now).
build your own I2C scanner with:
<speeds = 50 100 150 200 250 300 350 400 >
Arduino MultiSpeed I2C Scanner - 0.1.15
I2C ports: 1 Current: Wire0
@ = toggle Wire - Wire1 - Wire2 [TEENSY 3.5 or Arduino Due]
Scan mode:
s = single scan
c = continuous scan - 1 second delay
q = quit continuous scan
d = toggle latency delay between successful tests. 0 - 5 ms
i = toggle enable/disable interrupts
Output:
p = toggle printAll - printFound.
h = toggle header - noHeader.
a = toggle address range, 0..127 - 8..119 (default)
e = toggle . or errorCode e.g. E02
Speeds:
0 = 100..800 KHz - step 100 (warning - can block!!)
1 = 100 KHz
2 = 200 KHz
4 = 400 KHz
9 = 50..400 KHz - step 50 < DEFAULT >
!! HIGH SPEEDS - WARNING - can block - not applicable for UNO
8 = 800 KHz
M = 1000 KHz
N = 3400 KHz
O = 5000 KHz
P = 100 400 1000 3400 5000 KHz (standards)
r = reset to startup defaults.
? = help - this page
@ selects through the different Wire ports. Note that the current Wire port is given after I2C ports: count Wire0 is just Wire but it was easier to program.
s selects single scan mode, think of it as manual.
c selects continuous scanning, think of it as automatic.
q quits the continuous scan mode.
d toggles the latency between successful scans. Only needed sometimes.
i toggles disable/enable interrupts, use with care.
p toggles printAll and printFound. PrintAll will print also the addresses where nothing is found. PrintFound will only generate a line if an I2C device is found on that address.
h toggles the printing of a header.
a toggles the range of addresses scanned, default the range 8 .. 119 is scanned, but one can extend this range to 0 .. 127. Note: some addresses are reserved.
Experimental in 0.2.0
e toggles the output between . and the code returned by endTransmission(). When an device is found it will print OK. Might help for diagnosis, but one need to dive in the source code of the board. See table below for AVR.
Based on twi_writeTo(), other boards might have different codes.
Value Meaning
0 .. success
E01 .. length to long for buffer
E02 .. address send, NACK received
E03 .. data send, NACK received
E04 .. other twi error (lost bus arbitration, bus error, ..)
E05 .. timeout
All options here select a single speed or a range of speeds.
Since 0.1.10 version experimental speeds of 1000, 3400 and 5000 are added as
these are part of the I2C standards.
http://i2c.info/i2c-bus-specification
NOTE: not all processors will support these higher speeds. This can show up as blocking or it can even look like it is working. Check your datasheet to see which speeds are applicable for the processor in use.
- update documentation
- test on RP2040 and other platforms.
- add "T" command to toggle I2C_TIMEOUT 0 - 25000 ?
- non-AVR command behind a
#ifdef? - I2C GENERIC RESET address 0x00 CMD 0x06
- I2C GENERIC DEVICEID -> under investigation in PCA9671
- add watchdog reset (at least AVR - 8 seconds 0.2.0 ) => solved with I2C_TIMEOUT.
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