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boeseturbo
Joined: 23 Jul 2007
Posts: 65
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 Posted: Wed Jul 08, 2015 9:04 am Post subject: Soft-SPI working - HW-SPI not working |
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Hi friends,
I playing with a OLED display and use hkipniks SSD1306 code. I trying to convert Software-SPI to Hardware. I replaced shiftout with spiout command...
Config Spi = Soft , Din = Pinb.0 , Dout = Portb.2 , Ss = none , Clock = Portb.1
spiinit
REM Shiftout Data_out , Lcd_clk , Ddata(point) , 1 , 8 ', 2
spiout ddata(point),1
this code is working fine
When I try to use hardware SPI with my Arduino MEGA2560 with this code:
Config Spi = Hard, Interrupt = off, Data Order = msb, master = yes, Polarity = High, Phase = 1, Clockrate = 16, Noss = 1
spiinit
spiout ddata(point),1
it is not working.
SPI is connected right (Portb.2 MOSI to SDIN D1 - Portb.1 SCLK D0).
All other connections (ChipSelect, Reset, R/W) I leave like in the Software-SPI Test...
Has anybody an idea where my fault is?
Cheers
Paul
(BASCOM-AVR version : 2.0.7.8 ) |
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MWS
Joined: 22 Aug 2009
Posts: 2335
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| Posted: Wed Jul 08, 2015 9:28 am Post subject: Re: Soft-SPI working - HW-SPI not working |
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| boeseturbo wrote: | Config Spi = Hard, Interrupt = off, Data Order = msb, master = yes, Polarity = High, Phase = 1, Clockrate = 16, Noss = 1
Has anybody an idea where my fault is? |
You do not set the SS-pin to output, or pull it high while being input. Noss = 1 only says, that Bascom's spiout command does not take control over the SS-pin, nonetheless in master mode the SS-pin has to be configured as mentioned.
This is also stated in the help under Config SPI, it even is highlighted with an exclamation mark in yellow triangle, not to be missed by the user. |
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boeseturbo
Joined: 23 Jul 2007
Posts: 65
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| Posted: Wed Jul 08, 2015 9:44 am Post subject: |
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Hi,
I set the chipselect pin manually So I dont need SS pin of hardware SPI...
Cheers |
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boeseturbo
Joined: 23 Jul 2007
Posts: 65
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| Posted: Wed Jul 08, 2015 9:52 am Post subject: |
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I set now SS pin over hardware SPI, not manually set it. Now it is working...
Cheers and thank you very much for your tip!
Cheers |
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MWS
Joined: 22 Aug 2009
Posts: 2335
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| Posted: Wed Jul 08, 2015 10:11 am Post subject: |
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| boeseturbo wrote: | | I set now SS pin over hardware SPI, not manually set it. Now it is working... |
| Quote: | | I set the chipselect pin manually So I dont need SS pin of hardware SPI... |
It doesn't matter how you control CE of the hardware, you can hard wire it and have it disconnected from SS.
Critical however is, that you set the SS-pin to its required state for running SPI in master mode, this is simply a requirement by the SPI hardware within the AVR. |
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boeseturbo
Joined: 23 Jul 2007
Posts: 65
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| Posted: Fri Jul 10, 2015 8:00 am Post subject: |
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thank you very much for this information 
Cheers |
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Darthinvader
Joined: 09 Jul 2015
Posts: 4
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| Posted: Sat Jul 11, 2015 11:35 am Post subject: |
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Hi, i'm using this
Config >
Ddrb = &B10111110 : Spcr = &B01010000
Spdr = datatosend
Bitwait Spsr.7 , Set
I dont care about driving SS, just CE = 1 if i' sending data and thats it.
Working like a charm. |
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MWS
Joined: 22 Aug 2009
Posts: 2335
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| Posted: Sat Jul 11, 2015 5:30 pm Post subject: |
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| Darthinvader wrote: |
Ddrb = &B10111110 : Spcr = &B01010000
I dont care about driving SS, just CE = 1 if i' sending data and thats it.
Working like a charm. |
If you refer with your post to an ATMega2560, I'd say: don't distribute your nonsense, otherwise finally someone believes it and wonders why it won't work.
Your config shows SS (PINB0) to be set as input. In this configuration, SS has to be pulled high for master mode.
Whether this is done by static charge or a high value resistor, doesn't matter, as long the level on SS is high, it will work, only it would not be reliable.
If you don't understand the mechanisms of SPI, I'd advise to RTFM before posting. |
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Pzx
Joined: 05 May 2015
Posts: 39
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| Posted: Fri Feb 17, 2017 1:13 pm Post subject: |
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Hello,
can anyone post a link or copy whole Bascom code that is mentioned at the begining of this post? I can not find it.
Thanks in advance |
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