Handle I2C scan with specific call to HAL_I2C_IsDeviceReady #301
Conversation
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works on the bluepill board (stm32f103c8t6) i tested the i2c scanner and 5 different sensors on both i2c1 and i2c2, works flawlessly |
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works on stm32f103vet6 too (i made a custom board in the selection menu) |
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Please add to this PR also the scanner sketch that you are used (under Wire library examples). Thanks a lot for your work |
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@nikisalli would you mind pushing your proposed scanner sketch in a dedicated PR to help @Testato ? |
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PR with the scanner , tested an all three I2c for a Bluepill |
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hi @LMESTM , thanks for the patch. I just tested, using an arduino UNO as slave (standard test sketch), and on a discovery stm32f407 |
@MauroMombelli Have you added pull up resistors on the I2C lines ? |
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This PR Will Fix #298 |
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@LMESTM for sure the arduino is using its internal by default, not sure about this core. I can add some 4.7kohm resistor instead if you think this is the issue, but i don't see why it should work when i reboot the stm; technically any new scan should be completely independent from previous status of the bus, and leaving the system connected for a couple of scan should see the slave without need to reboot. |
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@MauroMombelli without pull-up resistors, plugging / unplugging the boards will lead to falling edges of the I2C lines which could lead to undesired behavior or possible lock-up of the bus. |
aren't the timeout there to avoid this issue? |
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I meant this probably leads to HW lock up ... so the need to reset the STM32. |
cores/arduino/stm32/twi.c
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| @@ -355,6 +355,11 @@ i2c_status_e i2c_master_write(i2c_t *obj, uint8_t dev_address, | |||
| uint32_t tickstart = HAL_GetTick(); | |||
| uint32_t delta = 0; | |||
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| /* When size is 0, this is usually a I2C scan / ping to check if device is there and ready */ | |||
When size is 0, the objective is to check if device is there and ready. A typical use case is to scan through all addresses to check for available slaves. So we're checking the various error cases to report to application.
Handle I2C scan with specific call to HAL_I2C_IsDeviceReady
Description
When size is 0, the objective is to check if device is there and ready.
A typical use case is to scan through all addresses to check for
available slaves.
So we're checking the various error cases to report to application.
Tests
I've run successfully the example sketch from #298 on:
NUCLEO_F429ZI
NUCLEO_F411RE
DISCO L475 IOT