On Tue, Nov 12, 2013 at 7:51 PM, joem joem@martindale-electric.co.uk wrote:
Try this :) it popped up on Google pretty quickly --> http://www.hobbytronics.co.uk/schottky-logic-level-conversion
: awesome. done. added to spec.
Same problem - access to the 3.3V power line inside the EOMA needed.
| no it is not. TTL 3v logic is somewhere around 2v for low. a small |reduction (such as using another shottky diode) would be enough.
Anyway - 3rd diagram added - modified version of Henrik's diagram for the EOMA: http://www.gplsquared.com/eoma_boot/eoma_boot.html#uart_repair
| great. 1.8+3.3=5.1 so the pull-up would be to 3.23V - enough to be |definitely below 3.3v.
Hmmmppp... pull ups don't work like you would expect under certain circumstances. I'm removing the 3rd diagram from here: http://www.gplsquared.com/eoma_boot/eoma_boot.html#uart_repair