How to establish 3 UART and 2 I2C interface at a same time in STM32F103C8T6?

Question

I am a newbie to STM32 and CubeMX. I need to create 3 UART interface and 2 I2C interface in STM32F103C8T6. I tried to, but there is a common port for both i2c and uart communication and it allows me to create only (2 uart and 2 i2c) or (3 uart and 1 i2c ) and I couldn't create as I needed . how can I establish 3 UART and 2 I2C interface at a same time in STM32F103C8T6 ?

Thanks in advance...

What's the reason for using two I2C interfaces? I2C is a bus. So a single bus can connect many devices. — Codo, Apr 16 '19 at 07:40
@Codo as log as they both are I2C masters and there is no address conflict. — followed Monica to Codidact, Apr 16 '19 at 10:09

score 3 · Answer 1 · answered Apr 16 '19 at 05:02

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You can't. There's an unresolvable pin conflict.

The I2C2 peripheral must use pins PB10 and PB11 for SDA and SCL -- there are no remappings for this peripheral.

The USART3 peripheral uses those pins for TX and RX. On higher pin-count STM32F1 parts, it can be remapped to pins PC10/PC11 or PD8/PD9; however, the STM32F103C8 doesn't have those pins.

There are only two I2C and three USART peripherals on the STM32F103, so there are no alternate I2C or USART peripherals available.

answered Apr 16 '19 at 05:02

1

Maybe you could use the 2 uart / 2 i2c solution and create the missing UART via software. As said by duskwuff, a pure hardware solution is not possible. – theSealion Apr 16 '19 at 07:37
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@theSealion implementing an I2C master in software would be simpler, as there are only minimum delay requirements. – followed Monica to Codidact Apr 16 '19 at 10:12
@berendi I would say that depends on his requirements. So maybe you are right or may I'm :-) – theSealion Apr 16 '19 at 10:40

score 1 · Answer 2 · answered Apr 16 '19 at 22:16

1

use hardware I2C and as many as possible hardware UARTS. For the additional ones write the software implementation. You have an example here: https://www.st.com/resource/en/application_note/dm00110292.pdf or take stm32F103 with more pins

answered Apr 16 '19 at 22:16

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How to establish 3 UART and 2 I2C interface at a same time in STM32F103C8T6?

2 Answers2