HI Guys; yes, me again. so i have gotten my liquidcrystal working, and have the shift register working. now i’m trying to combine the both. i have used this tutotial : http://playground.arduino.cc/Main/LiquidCrystal#ExtraPins to wire the setup up, nut now i’m stuck at translating this into a new…

I wonder if this has something to do with the SPI data output MOSI being defined as AF_OUTPUT_PUSHPULL instead of the more normal OUTPUT: https://github.com/spark/core-firmware/blob/master/src/spark_wiring_spi.cpp That funny intermediate voltage and those spikes make me think that the pin is not b…

Thanks @bko ! In the interest of “just trying it” I changed the SCK and MOSI pins to OUTPUT’s and SPI doesn’t even work anymore … it’s also locking up and not running the user code. Probably failing in the SPI init stages. I’ll keep looking! Probably would make sense to trim this down to JUST sen…

I just found the problem and fixed it! Arduino library was constantly re-configuring up the SPI which was glitching the bus: void LiquidCrystal::spiSendOut() //SPI ############################# { //just in case you are using SPI for more then one device //set bitOrder, clockDivider and dataMod…

I got a fix for the SPI glitch in the works… just capturing all of the scope plots to prove it works for all of the glitches then I will submit a pull request :wink: EDIT: Pull request submitted… if you are interested in the fixes now check it out: https://github.com/spark/core-firmware/pull/73

[image] BDub: void LiquidCrystal::spiSendOut() //SPI ############################# { //just in case you are using SPI for more then one device //set bitOrder, clockDivider and dataMode each time //SPI.setClockDivider (_clockDivider); //SPI.setBitOrder (_bitOrder); //SPI.setDataMode (_dataMode…

@BDub , Have you ever used a 74HC164 to interface with a LCD 16 x 2? It’s also a Serial in parallel out but less pricey than a 75HC595… http://sg.element14.com/nxp/74hc164n/ic-74hc-cmos-logic/dp/380623

I have not, but while it looks like half the price for DIP packages… the downside is it has no output latch, which means as you are shifting data into it, they are live on the outputs. This would make it basically impossible to create precise timing for a parallel input device… unless you only use …

Ah nice! I’ll definitely love to get the 595 then :smile: It’s like $12 vs $2 on element 14 which i thought was just too drastic! EDIT: Ah…the search function is the problem…they aren’t that pricey :smiley: Thinking of making a simple LCD shield but doubles up as a prototyping shield for people w…

[image] kennethlimcp: It's like $12 vs $2 on element 14 which i thought was just too drastic! Dang... on Digikey I was seeing $1.05 for the 595, and $0.47 for the 164. I was wondering why you splitting hairs over that price difference :wink: $10.00 more is definitely a problem! …

LiquidCrystal & Shift Register

Troubleshooting

BDub February 6, 2014, 5:59pm 38

Yeah there is an immediate fix… I just don’t call the SPI.setupstuff() in the spiSendOut() function anymore… but there is a ton of stuff I changed in the LiquidCrystal SPI library, so just hang tight I’m testing it now

EDIT: @korneel @Soulhuntre @Dave We’re live!

1 Like

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LiquidCrystal & Shift Register

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