Practical application of High Speed Design: WIFI transceiver James Lightner EECS713 - Fall 2017

What is a WIFI Transceiver? RF design varies The benefit of using a module Serial Communications Inclusion of the antenna varies between module. The benefit of using a module is that you don’t have to re-invent the whole wifi stack. They take care of all the encyption/ decoding/ and encryption

What Needs High Speed Design? Serial Communications I2C/I2S SPI SDIO UART USB Other digital lines Memory JTAG Design rules not specific to WIFI Transceiver I started project wanting to answer the question: If I want to include a module into my design, what do I need to know about high speed/ do I even need high speed?

Serial Communications Part Number SPI I2C UART SDIO USB Serial Communications TEXAS INSTRUMENTS CC3100 Cypress CYW43143 ATMEL ATWINC3400 Even modules with the same interfaces can be very different TEXAS INSTRUMENTS WL1837MOD

SDIO This is the same communication standard as “SD Cards” Iron man the movie is 5.08 GB in 1080p At default speed that is 6.8 minutes At UHS-III that is 13.8 seconds

“SDIO signals traces (CLK, CMD, D0, D1, D2, and D3) must be routed in parallel to each other and as short as possible (less than 12 cm). In addition, every trace length must be the same as the others. There should be enough space between traces – greater than 1.5 times the trace width or ground – to ensure signal quality, especially for the SDIO_CLK trace. Remember to keep these traces away from the other digital or analog signal traces. TI recommends adding ground shielding around these buses.” TI uses High speed and default speed for SDIO, specifying 3ns rise time 3ns rise time means a line length of about 4.16 inches in stripline configuration 12cm is about 4.72 inches

USB Transfer speeds for the un-viewable USB 1.0 – 1.5mb/s USB is 90 ohms differentail, so needs 45 ohm termination resistors USB 2.0 spec for Cypress CYW41343 USB 2.0 Spec is tr of 500ps .7 of an inch for stripline configuration

I2C Standard, Fast Mode and Fast Mode Plus Fastest transition time is 50ns 70 inches 100kb/s I2C was developed by NXP Iron Man in 11.28 hours

SPI Not Specified / Technology Specific For the ATMEL ATWINC15x0-MR210xB , rise time is 7ns SPI does not have a set speed and is dependent on the technology using it Rise time is 7ns meaning that you need to be under 10 inches

System Design Schematic and layout of the Cypress CYW43143 Thermal analysis Decoupling and bypass selection and placement Board stack design I chose Cypress because of its two fastest interfaces The rest of the report covers the rest of the Serial interfaces Design of a module to another package Detailed timing analyis Decoupling and bypass selection and placement Board stack design Transmission line design and routing

Questions?