NP-41 Emulator (may be)

[Chris Chung]

(12-06-2017 10:59 AM)Massimo Gnerucci Wrote:  

(12-06-2017 09:58 AM)Harald Wrote:  My Prototype has just died on me. A couple of days ago it wouldn't turn on.
The battery was drained so I replaced it. But it still didn't turn on and the battery was drained again quickly. I'll have to see what is going on....

Sad to know, egoistically I hope this is not the estimated ttl!

Too bad for you Harald, hope you will be able to fix it, it might just need a reflow on the chip area. My very 1st builds had problems when I applied too much solder, didn't use tools properly (they were mostly soldered, before I got the hot air gun). Those had ended as scraps.

The units I am shipping I had them assembled between March and May this year, the later ones you will find a date label on it. I knew they could have intermittent problems so I don't want to sell them ASAP and let them sit on their batteries. I would turn them on and run some calculations once or twice a week. The standby current is about 0.6uA while the active current should be around 10 mA (or less, can't remember). Over the summer I went travel and forgot about them. When I looked at them after 3 months, I found 1 unit couldn't turn on and 1 unit w/ "ghosted" LCD segments. The LCD is easy to fix by a simple reflow as I know the traces. The other unit I had to reflow the whole chip area. Only last month I decided to sell them as they appeared to be fine. I understand the chance of failure is higher on these units and reserved 2 units as replacements in case one of yours failed within a year. If it failed after one year, consider you paid for one year of entertainment.

(12-05-2017 09:30 PM)rprosperi Wrote:  It would be helpful if you could post a link to the proper (or at least equivalent) USB-serial cable - there are MANY different brands, configurations, chipsets, etc. and it would be nice to not waste time creating a list of the ones that don't work.

Any usb-serial that works on your computer should do. if you happens to have one, try it first.
The one I am using is the cheapest I can find that has 3.3V pin, plastic wrapped and it's $1. It is of a PL2303 chip and under Windows it reports a Polific USB-to-Serial Comm Port. Having one w/ 3.3V is better as it will ensure proper voltage during communication. Some devices have only 5V and you should avoid.

You will need also 4 female-female jumper cables, these are 20cm, mine in the photo are 10cm, there are longer ones if you need them on a desktop PC. Be sure to get those that can be separated as they need to be criss-crossed. At the back of the NP41 PCB you will find 4 pins marked "Rx Tx + G" for the serial connection. You will connect them to the Ground (G), 3.3V (+), Rx (Tx), Tx (Rx) signals from the usb-serial dongle.

Details / parameters for the download can be found here, they are the same as the prototype units Sylvain had before.