XK-1 power supply sequencing puzzle

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
User avatar
XCore Expert
Posts: 546
Joined: Thu Dec 10, 2009 10:41 pm
Location: St. Leonards-on-Sea, E. Sussex, UK.

XK-1 power supply sequencing puzzle

Post by leon_heller »

Does anyone know why the XK-1 power supply doesn't use a chip to ensure that the core supply isn't applied until the 3.3V supply is stable? Perhaps the linear regulator used always brings the 3.3V supply up quicker than the 1.0V switcher. Interestingly, the XS1-L1 reference design does have a sequencer chip, although that also uses a linear 3.3V regulator.

User avatar
XCore Legend
Posts: 1274
Joined: Thu Dec 10, 2009 10:20 pm

Post by Folknology »

It's a perfect example of how not to design the Xmos power sequencing ;-)
No supply sequencing & no power monitoring with RST_n/TRST_n
Respected Member
Posts: 282
Joined: Fri Mar 19, 2010 4:49 am

Post by bearcat »

The issue of power supply sequencing and JTAG reset's came out not long ago. It appears as XMOS redesigns the boards, they add the design criteria. I would review the latest reference designs to decide what is recommended.