SC18IS602 - SPI Timing

[JoergS]

Hello,

I use a SC18IS602 in my application.

I have analyzed I2C and SPI communication with a logic analyzer. After a I2C command to transmit some bytes on the SPI bus is received, the device starts transmitting the bytes on the SPI bus.

I am wondering why there is a delay of 8.8µs between the sent bytes on the SPI bus? The SPI clock is 1843 kHz. I have attached a screenshot

Greetings

Joerg

[TomasVaverka]

Hello Jörg,

I do not have the design specifications and cannot explain that since this device is pretty old (2006). However, based on our measurements, the idle time between the sent bytes is indeed around 9us when the SPI clock is at 1.8MHz. 

Best regards,

Tomas

[JoergS]

Thank you for your reply

The effective transfer rate is just approximately one-third. This is too slow in my application. I knew that I2C is much slower but I have to read out the data of a SPI slave with more than 1MHz because otherwise the data would be corrupted.

Is there a newer I2C to SPI bridge in your portfolio?

[TomasVaverka]

Hello Jörg,

Unfortunately there are not any newer I2C to SPI bridges in our portfolio.

Best regards.

Tomas