topic Re: SC18IS602 - SPI Timing in Other NXP Products

SC18IS602 - SPI Timing

JoergS — Mon, 09 Nov 2020 11:27:20 GMT

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

Re: SC18IS602 - SPI Timing

TomasVaverka — Mon, 09 Nov 2020 15:11:15 GMT

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

Re: SC18IS602 - SPI Timing

JoergS — Mon, 09 Nov 2020 15:33:20 GMT

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?

Re: SC18IS602 - SPI Timing

TomasVaverka — Mon, 09 Nov 2020 16:19:23 GMT

Hello Jörg,

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

Best regards.

Tomas