SPI to UART converter

elfrec

A micro controller only has one UART port. Therefore, we decide to use microcontroller SPI port as another UART2.

We need a SPI to UART converter (such as MAXIM3100 or NXP  - 161S752), however, this IC only supports SPI slave mode only. When we use it with this configuration:

a) Micro controller’s SPI (master) ------ “SPI (slave) to UART”-- PC’s UART
•        The communication is allowed.

b) PC’s UART ----- “UART to SPI(slave)” -- Micro controller’s SPI (master)
•        The communication is not allowed as slave is unable to initiate talk with master.

May I know any SPI to UART converter IC can support Master SPI? Or do you all have other solution, thank you!

scholler

1、“b) PC’s UART ----- “UART to SPI(slave)” -- Micro controller’s SPI (master)
• The communication is not allowed as slave is unable to initiate talk with master.”
I think, that is interrut with the SPI to UART converter when PC's UART send data to it.You can detect the interrupt bit and use SPI to read the SPI to UART converter.Therefore,you can connect the SPI to UART converter's interrupt Pin with the Micro controller's external interrupt Pin.You can detect the SPI to UART converter's interrupt in real time through the external interrupt.
2、 Use the micro controller such as C8051F340,which has 2 UARTs.

elfrec

Yeah, scholler. I think that is the point. Thank you.

However, which party will generate the interrupt signal?
Can I say that the interrupt signal is generated from the RTS or CTS signal?



For your information, we cannot change microcontroller due to inventory available.

Thank you,

scholler

Dear Elfrec:

    I read the datasheet of MAX3100, and find that the MAX3100 has the interrupt Pin /IRQ.See page 6 of the MAX3100's datasheet, when the TM(TRANSMIT-DONE),RM(DATA-RECEIVED),PM and RAM happened,the interrupt Pin /IRQ set to be 0. Use the SPI bus to read the TM,RM,PM and RAM mask bit /TM,/RM,PM/ and /RAM,see the page 8 Table 2. if the /RM 's value has been changed,you can use the SPI bus to read the data such as page 8 Table 4.See the Interrupt Sources and Masks at page 11.

scholler

elfrec

高手，高手~想不到这个论坛素质那么高，我以为没人会鸟我的英文。 我比较擅长RF的东西，下次有什么问题可以PM我，谢谢！

Powerful! It is unexpected that the quality of this forum can be that high. I thought everyone will ignore me due to my english writing. I am more familiar with the RF knowledge, please PM me next time if you have any problem. Thank you!