2023-09-09 02:43 AM
I am trying to implement LCD and AMS5812 Sensor on I2C3 Bus,
But AMS5812 I2C sensor is holding the I2C bus and preventing further scanning STM32F407G Discovery board.
/*-[ I2C Bus Scanning ]-*/
HAL_UART_Transmit(&huart2, (uint8_t *)StartMSG, sizeof(StartMSG), 10000);
for(i=1; i<128; i++)
{
ret = HAL_I2C_IsDeviceReady(&hi2c3, (uint16_t)(i<<1), 3, 5);
if (ret != HAL_OK) /* No ACK Received At That Address */
{
HAL_UART_Transmit(&huart2, (uint8_t *)Space, sizeof(Space), 10000);
}
else if(ret == HAL_OK)
{
sprintf(Buffer, "0x%X", i);
HAL_UART_Transmit(&huart2, (uint8_t *)Buffer, sizeof(Buffer), 10000);
}
}
HAL_UART_Transmit(&huart2, (uint8_t *)EndMSG, sizeof(EndMSG), 10000);
/*--[ Scanning Done ]--*/
HAL_Delay(1000);
AMS5812 sensor is working on 5V and i2c LCD is also working on 5V. i am using 5V to 3V level shifter as below.
first time i2c Scanning code detect lcd address as 0x27 and then blank.
Expected 0x27 and 0x78
I have tried using 3.1K pull up resistors but no benefit on both the sides of level shifter.
Please advise where i could be wrong ?
2023-09-09 04:46 AM
Your converter also needs supply voltage and GND
LV = 3V, HV=5V, GND = GND
2023-09-09 04:58 AM
Hello @asking
Can you add your code to take a look on it. Also, can you try using just the LCD.
Best regards.
II
2023-09-09 05:59 AM
Yes, only LCD works fine. also other I2C Devices like SM Pressure sensors works fine. Only problem is AMS5812 when i put on bus. No further scanning only - - - - .
Core is simple I2C Discovery code. i have enabled I2C3 with 400000HZ Fast Mode.
2023-09-09 06:00 AM
Yes i have connected LV to 3V, HV to 5V and GND to System GND Common for all systems.
2023-09-09 06:16 AM
Can you try using another I2C
2023-09-10 09:25 PM
Yes, i will try another i2c bus and update.
2023-09-11 02:17 AM
Hello @asking ,
The silver dot on the AMS 5812 marks the location of Pin 1. The AMS 5812 pinout is:
4.7 kOhm resistors should be used as pullups on SDA and SCL, these resistors should pullup with a 5V source.
Foued
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2023-09-14 02:12 AM
Yes i have double checked the connection. now trying with scope on I2C Bus....
2023-09-14 04:42 AM - edited 2023-09-14 04:44 AM
SCL / SDA on Scope. Below Observations.
With AMS5812 Sensor, Peak is curved.
Yellow is SDA and Violet is SCL
Without AMS5812 Sensor. I2C Scanner works fine.