![]() ![]() I solved this by using more complex circuit: TTL (5V) to LV-TTL (3,3V) buffers (74xx125 - HC or LX don't remember), SN75189 + SN75188 (one is EIA/232 driver other is receiver - don't remember which one is which), two DC/DC: +12V 50mA, -12V 50mA - but at that time I was using FT8U232 (or something like that, from FTDI - one of first USB-serial converters). But, wait, humans learns on mistakes, especially those that cost a bit moreĪs for MAX'es - yes MAX3232 works with 3,3V logic but I had a quiet few problems with it because of rs232 levels, old tech is a bi*ch when it comes to rs232 levels - it's very picky, usually if chip can't supply at least +11V/-11V with few mA (up to around 5-8mA) current then the old junk just ignore what you send. If he connected directly RS232 to RPi then at least Rx line is soo cold dead. The simplest way is to add a decoupling capc (on power rails) as close as possible ICs, adding also small R in serial in signal lines and few pF caps close to inputs helps too, but I would focus on IC power lines decoupling for now (100nF + 1.10uF tantalum cap). I think the garbage is coming from noise (electrical ) from machine and environment, it's nasty thing and sometimes it can be difficult to deal with. Download CoolTerm for Windows to monitor, troubleshoot, debug, or test serial port connections and performance CoolTerm has had 2 updates within the past 6 months. Is there a level shifter rs232 that can emulate rts and cts signal and leave to rpi2 only rtx anc trx, may you send me a link to such device?Ĭould be that the rpi2 ttyAMA0 works only at 115200? seems to me that there are many projects out there that uses different port boudrate.Ībonvici - write "only trx rtx and gnd throught a level shifter" - so he using a level shifter, and he also tested RPi with PC with adapters and cables, and this work. So is there a way to understand whats going wrong? Seems to me that should not be a sync problem: the baudrate 9600 work well on windows so i set the same baudrate on rpi2.i know that rpi2 mini uart is non full flegded com port (lack of cts rts), coud be this ? The rpi 2 mini uart work well because before connecting to engel machine i connected it to my computer com1 and exchanged data rpi2 pc for many hours. The port configuration is the same as windows, the cable the same too. ![]() ![]() The problem is that, with the same port config than that of windows (9600 8N1), on rpi 2 i get a bunch of garbage. On rpi2 i used minicom to dump the strings on screen before save them. So I connected the same cable to the rpi mini uart (only trx rtx and gnd throught a level shifter) and try to register the paramaterrs string as i did in windows. But when I try to send out message from Max to. If i connect the serial cable to a normal pc, com1 port ,I see the parameters printed on screen by mean of a simple terminal softare: windows coolterm. One of them with a Max Patch which can monitor the input from CoolTerm input from the other computer. An Engel moulding machine print a set of parameters to a serial interface. I tried to emulate an old serial printer with raspberry PI 2. ![]()
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