FantomXR Posted April 8, 2017 Report Share Posted April 8, 2017 (edited) Hey people, what is the meaning of the RC1 and RC2 lines on digital modules? I wonder that the official schematic of the DOUT-module uses only one select line:http://ucapps.de/mbhp/mbhp_doutx4_r5.pdf the DIN-module uses bothhttp://ucapps.de/mbhp/mbhp_dinx4_r5.pdf and the DIO-module also only uses one:http://ucapps.de/mbhp/mbhp_dio_matrix.pdf I ask because I made a PCB that works perfectly when connected to the core directly but stops working as soon as a DIO-module is between the PCB and the core. If I put the DIO behind the PCB it works also... but not the other way around... on the PCB I have addressed RC1 to HC165 and RC2 to HC595. As the DIO doesn't seem to forward the RC2 this seems to make sense... Can anybody confirm that? Thanks, Chris //edit: I checked the LRE-PCB and he also addressed RC1 and RC2 like me.http://jeromebo.free.fr/Wiki/MB-LRE8x2CS_Rev4.6/Schematic_MB-LRE8x2CS_Rev4.6.pdf But I wonder how the DIO can work with both HC165 and HC595 connected to the same RC-line... Edited April 8, 2017 by FantomXR Quote Link to comment Share on other sites More sharing options...
latigid on Posted April 8, 2017 Report Share Posted April 8, 2017 (edited) If you look at the old PIC8 Core, there was only a single RC line. Now they are separated (different MCU pins and also buffered), but RC1 and RC2 send latch pulses at the same time. I.e. for the moment (and foreseeable future) there's no practical difference between them. This is not the case for other SPI ports, like J19 or J16, where the RCs are "chip selects" for separate peripherals. When Wilba did his SEQ PCB, he simply bussed the two RCs together. My guess is running data busses in parallel is more important when you have chains of DIN/DOUT separated over multiple PCBs, rather than BLMs etc. on a single PCB. Still, the best practice is apparently to split both RC and SC (!) and run whole chains of DIN/DOUT. The SC on the output header is best sourced from the longer chain (either DIN or DOUT): More to the point of your build, RC1 should be routed with the DOUT side, and RC2 with the DIN side. You've done it the other way around. I don't have any DIOMATRIX modules, but from the schem TK. is not following his own guidelines . Because RC2 isn't connected on DIOMATRIX, and your PCBs correctly spilt them, then the result is no connection for the RC2 line on your PCB. I think you can solve this by bridging RC1 -> RC2 on one of the headers e.g. on the output of DIOMATRIX or the input of your board. Edited April 8, 2017 by latigid on Quote Link to comment Share on other sites More sharing options...
FantomXR Posted April 8, 2017 Author Report Share Posted April 8, 2017 Thanks for your reply! I'll try tomorrow what you suggested and will report back. Do I get you right that you suggest to split RC as well as SC for 165 and 595? I don't want to change all PCBs I've made so far... so I hope it's not a problem to bridge RC1 and RC2... Quote Link to comment Share on other sites More sharing options...
latigid on Posted April 9, 2017 Report Share Posted April 9, 2017 I route up my boards using separate traces for RC1 and RC2, and I split SC into SC_DOUT and SC_DIN if it's practical. Hopefully it works to tie RC1 and RC2 together where it's needed. IMO it's the "least critical" signal of the SRIO chain as it just tells the shift register when to transfer the 8 bits from storage to the outputs in the case of DOUT, or when to scan the inputs for DIN. Quote Link to comment Share on other sites More sharing options...
FantomXR Posted April 9, 2017 Author Report Share Posted April 9, 2017 Okay! I confirm, that this works... you have to connect RC1 and RC2 of the DIO together if you have PCBs after that that splits RC1 and RC2... Thanks for your help and explanation! Quote Link to comment Share on other sites More sharing options...
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