Ten Things You Want to be Sure to put into Your SOC

I’ve just spent the day at DVcon in San Jose and met a friend of mine, Gary Stringham, who consults on SOC and embedded systems design. He spent years designing laser printers around SOCs at HP and he’s learned a thing or two about the trials and tribulations of SOC design. Gary’s just published a book, Hardware/Firmware Interface Design: Best Practices for Improving Embedded Systems Development. Embedded within the book are 300 best practices. I also picked up a brochure from Gary’s DVcon booth titled “Ten Hooks You’ll Wish You Had in Your Chip.” I like the brochure and the book. I can’t reproduce the book’s 300 best practices but I can give you the ten eminently practical things you’ll wish you’d put into your chip:

1.       Make address and counter registers firmware-readable.

2.       Provide a firmware-register that contains the current state of each state machine.

3.       Provide read access to many signals internal to the chip through a register.

4.       Provide read access to the current state of key input and output signal pins through a register.

5.       Provide non-destructive read access to internal memory including FIFOs and buffers. Also include read access to memory management registers and to the counters used for head and tail pointers.

6.       Provide a register with control bits connected to the power-on resets for each block on the chip.

7.       Provide a separate test and debug interrupt module that will generate interrupts from different internal signals.

8.       Provide means within a block to simulate external signals, which may be as simple as setting a bit or by enabling a signal pattern generator.

9.       Provide points in the middle of a pipeline where firmware can pull data out of or put data into a pipeline.

10.   For countdown timers that reload and then continue counting when an event occurs, save a copy of the timer value just prior to the event in a separate register that’s firmware readable.

Perhaps Gary’s approach sounds like the kind of help you’d like on your next (or current) SOC design project. Check out his free newsletter: http://garystringham.com/newsletter.shtml.