STM32F103 with CAN and USB?

[markusmueller19]

Posted on April 17, 2008 at 10:58

STM32F103 with CAN and USB?

[markusmueller19]

Posted on May 17, 2011 at 12:30

Hello,

In datasheet have I read, CAN and USB cannot use at same time. At beginn, I was very happy to fouund a CPU with pheripherials what I need: - 12Bit AD - 3x PWM - Serial - IIC - USB - CAN - Low Pin Count 48 Then I have start the development, but when I cannot use both CAN and USB, then I cannot use this controller. Gives a other solution for me? Want ST make a CPU without this bug, an the same pin configuration (and without the pin configuration bugs from errata)? In my application, I need 12Bit AD and minimum 16Bit RISC CPU. Thank you very much for answer. Regards Markus.

[ivanov-i]

Posted on May 17, 2011 at 12:30

Hi Markus,

It seems from the datasheet that CAN could be remaped on PB8 and PB8. They are available on all devices, except the 36-pin one. Also, the only limitation about CAN is its usage together with USART1_RTS. It should be possible to use the CAN and USB together. Regards, Ivan

[markusmueller19]

Posted on May 17, 2011 at 12:30

Hello Ivan,

Sorry, my english is not so good, but I have look in the datasheet RM0008, page 383, (Content 17.2) vvvvvv Note: The USB and CAN share a dedicated 512-byte SRAM memory for data transmission and reception, and so they cannot be used concurrently (the shared SRAM is accessed through CAN and USB exclusively). The USB and CAN can be used in the same application but not at the same time. ^^^^^^ It is not a problem from the port pins. I think, I cannot use both at same time!?? Regards Markus.

[ivanov-i]

Posted on May 17, 2011 at 12:30

Hi Markus,

I missed it. It is strange, indeed, to have such a limitation. I am sure you could find a chip with CAN and USB together from NXP, but they offer only 10-bit ADC. May be you could use them with an external chip? Regards, Ivan

[16-32micros]

Posted on May 17, 2011 at 12:30

Hi all,

This is not a limitation, But it was done on purpose to have such lower price of STM32 :-), I have another alternative : you can have two STM32 connected with GPIOs or SPI : one handling USB and the the other CAN :-). Cheers, STOne-32.

[jj]

Posted on May 17, 2011 at 12:30

There are TWO additional benefits in following STOne's

suggestion: a) higher speed as each micro can focus on specific task b) often you can use smaller, simpler, lower cost part by dividing the task The abundance of I/O makes ''inter processor'' exchanges easy with the STM32 family.

[markusmueller19]

Posted on May 17, 2011 at 12:30

Yes, the NXP devices have only 10Bit, but I need 12Bit AD.

A other device dsPIC30F5011 have 12Bit, too, but no USB (For USB I need a PIC18F2450 extra!). For my current application is CAN only a option for future, then the STM32 is the better solution. My board must be very very small and low cost, so I cannot implement additional chips. If ST can make a STM32F103xB witch included CAN and USB for using at same time, then it is for my company for interest in the feature. Thank you very much. [ This message was edited by: markus.mueller on 16-04-2008 15:06 ]

[er2]

Posted on May 17, 2011 at 12:30

Hi Markus,

we both have the same problem and we both are not very good in english. Please contact me in german via E-Mail:

mailto:er@er-tronic.de

Erwin