Multiprocessor communication using SPI

#1 · October 18, 2024, 5:29 pm

Quote from tomas714 on October 18, 2024, 5:29 pm
Hello,

I am trying to create a program in which seven microcontrollers communicate with each other using SPI. One is master and six are slaves. I used a classic configuration where MISO MOSI and SCK are shared and SS pins are separate for each microcontroller.

Data sending works fine. I send numbers from 0 to 255 which are displayed on the D port of the slave device. For control I send the same data back to the master device. But the MISO pin fights with the other MISO pins.
First I used ATmega8 as slave but in datasheet on page 125 (datasheet) I found that after SS is high all SPI pins except MISO are inputs.

So I used as slave ATmega48 where in datasheet on page 174 (datasheet) says that after SS is high all SPI pins are inputs.
Despite this, the MISO pins seem to interfere with each other.

Can you help me with this?

Thank you and have a nice day.

Regards
tomas714

PS: I don't know why but the attached files are not displayed. I tried to edit the post but it doesn't work.

[spoiler title="master.hex"]

:100000000C9434000C9498000C9498000C94980074
:100010000C9498000C9498000C9498000C94980000
:100020000C9498000C9498000C9498000C949800F0
:100030000C9498000C9498000C9498000C949800E0
:100040000C9498000C9498000C9498000C949800D0
:100050000C9498000C9498000C9498000C949800C0
:100060000C9498000C94980011241FBECFEFD8E098
:10007000DEBFCDBF0E947F000C948A00F894FFCFB2
:100080004BB121E030E0F90102C0EE0FFF1F8A956D
:10009000E2F7CF012E2F209542234BB96EBD0DB450
:0E00A00007FEFDCF9BB1892B8BB98EB508955D
:1000AE008AB18F638AB98BB18F638BB9239A259AE4
:1000BE008CB580648CBD8CB580618CBD8CB5816037
:0A00CE008CBD8DB581608DBD0895D5
:1000D800CF93DF93D0E00AC06D2F8C2F0E94400091
:1000E800CF5FC630C9F7DF5FDF3F11F0C0E0F4CF64
:0600F800DF91CF91089595
:1000FE008DB79EB701960E9495008DB79EB701965B
:06010E000E946C00FACF14
:10011400EC010E949D000E949C00CE010E949E0062
:06012400CE010E949A00CA
:06012A000E945700089539
:040130000C9400002B
:040134000E943E00E7
:02013800089528
:02013A00089526
:02013C00089524
:00000001FF

[/spoiler]

[spoiler title="slave.hex"]

:1000000019C04DC04CC04BC04AC049C048C047C0D1
:1000100046C045C044C043C042C041C040C03FC0CC
:100020003EC03DC03CC03BC03AC039C038C037C0FC
:1000300036C035C011241FBECFEFD2E0DEBFCDBF2A
:080040000ED01DC0F894FFCFA3
:10004800249A8CB580648CBD8CB581608CBD8DB5CF
:0600580081608DBD0895DA
:10005E008DB79EB701961AD08DB79EB7019601D077
:02006E00FBCFC6
:0E0070008FEF8AB90BD08BB98BB10DD00895EC
:0E007E00EC0110D00ED0CE010ED0CE010DD070
:0A008C000DB407FEFDCF8EB50895F8
:040096008EBD08957E
:04009A00D6DF089510
:02009E00B0CFE1
:0200A0000895C1
:0200A2000895BF
:0200A4000895BD
:0200A600CEDFAB
:00000001FF

[/spoiler]

[spoiler title="simulide.sim1"]

<circuit version="1.1.0-SR1" rev="2006" stepSize="1000000" stepsPS="10000" NLsteps="100000" reaStep="1000000" animate="1" >

<item itemtype="MCU" CircId="mega328-25" mainComp="false" Show_id="true" Show_Val="false" Pos="-828,-116" rotation="0" hflip="1" vflip="1" label="Main Controller" idLabPos="-14.2317,-18.221" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="master.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="true" SerialMon="-1" />

<item itemtype="Battery" CircId="Battery-33" mainComp="false" Show_id="false" Show_Val="false" Pos="-828,108" rotation="90" hflip="1" vflip="1" label="Battery-33" idLabPos="-18,-22" labelrot="0" valLabPos="-10,10" valLabRot="0" Voltage="5 V" Resistance="1 mΩ" />

<item itemtype="Ground" CircId="Ground-34" mainComp="false" Show_id="false" Show_Val="false" Pos="-828,156" rotation="0" hflip="1" vflip="1" label="Ground-34" idLabPos="-16,8" labelrot="0" valLabPos="-16,20" valLabRot="0" />

<item itemtype="Tunnel" CircId="Tunnel-35" mainComp="false" Show_id="false" Show_Val="false" Pos="-780,84" rotation="360" hflip="-1" vflip="1" label="Tunnel-35" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Capacitor" CircId="Capacitor-41" mainComp="false" ShowProp="Capacitance" Show_id="false" Show_Val="true" Pos="-788,108" rotation="450" hflip="1" vflip="1" label="Capacitor-41" idLabPos="-16,-24" labelrot="0" valLabPos="6.761,-3.10217" valLabRot="-90" Capacitance="1 µF" Resistance="1 µΩ" InitVolt="0 V" ReaStep="0 ns" />

<item itemtype="Tunnel" CircId="Tunnel-47" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-36" rotation="360" hflip="1" vflip="1" label="Tunnel-47" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-50" mainComp="false" Show_id="false" Show_Val="false" Pos="-652,-36" rotation="360" hflip="1" vflip="1" label="Tunnel-50" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-62" mainComp="false" Show_id="false" Show_Val="false" Pos="-452,-36" rotation="360" hflip="1" vflip="1" label="Tunnel-62" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-64" mainComp="false" Show_id="false" Show_Val="false" Pos="-252,-36" rotation="360" hflip="1" vflip="1" label="Tunnel-64" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-66" mainComp="false" Show_id="false" Show_Val="false" Pos="-652,156" rotation="360" hflip="1" vflip="1" label="Tunnel-66" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-67" mainComp="false" Show_id="false" Show_Val="false" Pos="-452,156" rotation="360" hflip="1" vflip="1" label="Tunnel-67" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-68" mainComp="false" Show_id="false" Show_Val="false" Pos="-252,156" rotation="360" hflip="1" vflip="1" label="Tunnel-68" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="+5V" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-73" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,-68" rotation="-360" hflip="-1" vflip="1" label="Tunnel-73" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-74" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,-76" rotation="-360" hflip="-1" vflip="1" label="Tunnel-74" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-75" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,-84" rotation="-360" hflip="-1" vflip="1" label="Tunnel-75" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-76" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,-92" rotation="-360" hflip="-1" vflip="1" label="Tunnel-76" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-0" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-77" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,-92" rotation="-360" hflip="-1" vflip="1" label="Tunnel-77" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-1" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-78" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,-68" rotation="-360" hflip="-1" vflip="1" label="Tunnel-78" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-79" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,-76" rotation="-360" hflip="-1" vflip="1" label="Tunnel-79" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-80" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,-84" rotation="-360" hflip="-1" vflip="1" label="Tunnel-80" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-81" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,-92" rotation="-360" hflip="-1" vflip="1" label="Tunnel-81" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-2" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-82" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,-68" rotation="-360" hflip="-1" vflip="1" label="Tunnel-82" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-83" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,-76" rotation="-360" hflip="-1" vflip="1" label="Tunnel-83" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-84" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,-84" rotation="-360" hflip="-1" vflip="1" label="Tunnel-84" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-85" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,100" rotation="-360" hflip="-1" vflip="1" label="Tunnel-85" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-3" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-86" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,124" rotation="-360" hflip="-1" vflip="1" label="Tunnel-86" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-87" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,116" rotation="-360" hflip="-1" vflip="1" label="Tunnel-87" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-88" mainComp="false" Show_id="false" Show_Val="false" Pos="-564,108" rotation="-360" hflip="-1" vflip="1" label="Tunnel-88" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-89" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,100" rotation="-360" hflip="-1" vflip="1" label="Tunnel-89" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-4" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-90" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,124" rotation="-360" hflip="-1" vflip="1" label="Tunnel-90" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-91" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,116" rotation="-360" hflip="-1" vflip="1" label="Tunnel-91" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-92" mainComp="false" Show_id="false" Show_Val="false" Pos="-364,108" rotation="-360" hflip="-1" vflip="1" label="Tunnel-92" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-93" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,100" rotation="-360" hflip="-1" vflip="1" label="Tunnel-93" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-5" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-94" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,124" rotation="-360" hflip="-1" vflip="1" label="Tunnel-94" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-95" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,116" rotation="-360" hflip="-1" vflip="1" label="Tunnel-95" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-96" mainComp="false" Show_id="false" Show_Val="false" Pos="-164,108" rotation="-360" hflip="-1" vflip="1" label="Tunnel-96" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-97" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-108" rotation="-360" hflip="1" vflip="1" label="Tunnel-97" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-0" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-98" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-100" rotation="-360" hflip="1" vflip="1" label="Tunnel-98" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-1" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-99" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-92" rotation="-360" hflip="1" vflip="1" label="Tunnel-99" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-2" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-100" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-84" rotation="-360" hflip="1" vflip="1" label="Tunnel-100" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-3" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-101" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-76" rotation="-360" hflip="1" vflip="1" label="Tunnel-101" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-4" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-102" mainComp="false" Show_id="false" Show_Val="false" Pos="-852,-68" rotation="-360" hflip="1" vflip="1" label="Tunnel-102" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-5" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-103" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-68" rotation="-360" hflip="-1" vflip="1" label="Tunnel-103" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-104" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-76" rotation="-360" hflip="-1" vflip="1" label="Tunnel-104" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-105" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-84" rotation="-360" hflip="-1" vflip="1" label="Tunnel-105" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Oscope" CircId="Oscope-111" mainComp="false" Show_id="false" Show_Val="false" Pos="-660,-268" rotation="0" hflip="1" vflip="1" label="Oscope-111" idLabPos="-90,-100" labelrot="0" valLabPos="-16,20" valLabRot="0" Basic_X="135 _px" Basic_Y="135 _px" BufferSize="600000" connectGnd="true" InputImped="10 MΩ" TimDiv="4920637" TimPos="0,0,0,0," VolDiv="1,1,1,1," Tunnels=",,,," Trigger="3" Filter="0.1 V" AutoSC="4" Tracks="4" HideCh="false,false,false,false," VolPos="-2.49999,-0.416666,-2.49999,-2.47525," />

<item itemtype="Tunnel" CircId="Tunnel-112" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-284" rotation="-360" hflip="1" vflip="1" label="Tunnel-112" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MISO" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-113" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-252" rotation="-360" hflip="1" vflip="1" label="Tunnel-113" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="SCK" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-114" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-316" rotation="-360" hflip="1" vflip="1" label="Tunnel-114" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="MOSI" IsBus="false" />

<item itemtype="Tunnel" CircId="Tunnel-115" mainComp="false" Show_id="false" Show_Val="false" Pos="-764,-220" rotation="-360" hflip="1" vflip="1" label="Tunnel-115" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Name="CS-0" IsBus="false" />

<item itemtype="MCU" CircId="mega48-116" mainComp="false" Show_id="true" Show_Val="false" Pos="-628,-116" rotation="0" hflip="1" vflip="1" label="0. Lobe Controller" idLabPos="-20.0025,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="MCU" CircId="mega48-118" mainComp="false" Show_id="true" Show_Val="false" Pos="-428,-116" rotation="0" hflip="1" vflip="1" label="1. Lobe Controller" idLabPos="-20.8953,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="MCU" CircId="mega48-120" mainComp="false" Show_id="true" Show_Val="false" Pos="-228,-116" rotation="0" hflip="1" vflip="1" label="mega48-120" idLabPos="-20.8953,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="MCU" CircId="mega48-121" mainComp="false" Show_id="true" Show_Val="false" Pos="-628,76" rotation="0" hflip="1" vflip="1" label="mega48-121" idLabPos="-20.8953,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="MCU" CircId="mega48-122" mainComp="false" Show_id="true" Show_Val="false" Pos="-428,76" rotation="0" hflip="1" vflip="1" label="mega48-122" idLabPos="-20.8953,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="MCU" CircId="mega48-123" mainComp="false" Show_id="true" Show_Val="false" Pos="-228,76" rotation="0" hflip="1" vflip="1" label="mega48-123" idLabPos="-20.8953,-19.3749" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="8 MHz" Program="slave.hex" Auto_Load="true" saveEepr="true" Logic_Symbol="true" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" Clk_Out="false" MainMcu="false" SerialMon="-1" />

<item itemtype="Node" CircId="Node-42" mainComp="false" Pos="-828,132" />

<item itemtype="Node" CircId="Node-43" mainComp="false" Pos="-788,84" />

<item itemtype="Node" CircId="Node-48" mainComp="false" Pos="-844,-36" />

<item itemtype="Node" CircId="Node-117" mainComp="false" Pos="-644,-36" />

<item itemtype="Node" CircId="Node-119" mainComp="false" Pos="-444,-36" />

<item itemtype="Node" CircId="Node-124" mainComp="false" Pos="-244,-36" />

<item itemtype="Node" CircId="Node-125" mainComp="false" Pos="-644,156" />

<item itemtype="Node" CircId="Node-126" mainComp="false" Pos="-444,156" />

<item itemtype="Node" CircId="Node-127" mainComp="false" Pos="-244,156" />

<item itemtype="Connector" uid="Connector-110" startpinid="Battery-33-rPin" endpinid="Node-42-0" pointList="-828,124,-828,132" />

<item itemtype="Connector" uid="Connector-111" startpinid="Node-42-2" endpinid="Ground-34-Gnd" pointList="-828,132,-828,140" />

<item itemtype="Connector" uid="Connector-112" startpinid="Capacitor-41-lPin" endpinid="Node-43-1" pointList="-788,92,-788,84" />

<item itemtype="Connector" uid="Connector-114" startpinid="Node-43-2" endpinid="Battery-33-lPin" pointList="-788,84,-828,84,-828,92" />

<item itemtype="Connector" uid="Connector-122" startpinid="mega328-25-PORTV0" endpinid="Node-48-1" pointList="-836,-28,-844,-28,-844,-36" />

<item itemtype="Connector" uid="Connector-123" startpinid="Tunnel-47-pin" endpinid="Node-48-0" pointList="-852,-36,-844,-36" />

<item itemtype="Connector" uid="Connector-124" startpinid="Node-48-2" endpinid="mega328-25-PORTV1" pointList="-844,-36,-836,-36" />

<item itemtype="Connector" uid="Connector-155" startpinid="Capacitor-41-rPin" endpinid="Node-42-1" pointList="-788,124,-788,132,-828,132" />

<item itemtype="Connector" uid="Connector-156" startpinid="Tunnel-35-pin" endpinid="Node-43-0" pointList="-780,84,-788,84" />

<item itemtype="Connector" uid="Connector-181" startpinid="Tunnel-97-pin" endpinid="mega328-25-PORTD0" pointList="-852,-108,-836,-108" />

<item itemtype="Connector" uid="Connector-182" startpinid="mega328-25-PORTD1" endpinid="Tunnel-98-pin" pointList="-836,-100,-852,-100" />

<item itemtype="Connector" uid="Connector-183" startpinid="Tunnel-99-pin" endpinid="mega328-25-PORTD2" pointList="-852,-92,-836,-92" />

<item itemtype="Connector" uid="Connector-184" startpinid="mega328-25-PORTD3" endpinid="Tunnel-100-pin" pointList="-836,-84,-852,-84" />

<item itemtype="Connector" uid="Connector-185" startpinid="Tunnel-101-pin" endpinid="mega328-25-PORTD4" pointList="-852,-76,-836,-76" />

<item itemtype="Connector" uid="Connector-186" startpinid="mega328-25-PORTD5" endpinid="Tunnel-102-pin" pointList="-836,-68,-852,-68" />

<item itemtype="Connector" uid="Connector-199" startpinid="mega328-25-PORTB5" endpinid="Tunnel-103-pin" pointList="-780,-68,-764,-68" />

<item itemtype="Connector" uid="Connector-200" startpinid="mega328-25-PORTB3" endpinid="Tunnel-105-pin" pointList="-780,-84,-764,-84" />

<item itemtype="Connector" uid="Connector-201" startpinid="Tunnel-104-pin" endpinid="mega328-25-PORTB4" pointList="-764,-76,-780,-76" />

<item itemtype="Connector" uid="Connector-202" startpinid="Tunnel-114-pin" endpinid="Oscope-111-Pin0" pointList="-764,-316,-748,-316" />

<item itemtype="Connector" uid="Connector-203" startpinid="Tunnel-112-pin" endpinid="Oscope-111-Pin1" pointList="-764,-284,-748,-284" />

<item itemtype="Connector" uid="Connector-204" startpinid="Tunnel-113-pin" endpinid="Oscope-111-Pin2" pointList="-764,-252,-748,-252" />

<item itemtype="Connector" uid="Connector-205" startpinid="Tunnel-115-pin" endpinid="Oscope-111-Pin3" pointList="-764,-220,-748,-220" />

<item itemtype="Connector" uid="Connector-213" startpinid="mega48-116-PORTV0" endpinid="Node-117-1" pointList="-636,-28,-644,-28,-644,-36" />

<item itemtype="Connector" uid="Connector-214" startpinid="Tunnel-50-pin" endpinid="Node-117-0" pointList="-652,-36,-644,-36" />

<item itemtype="Connector" uid="Connector-215" startpinid="Node-117-2" endpinid="mega48-116-PORTV1" pointList="-644,-36,-636,-36" />

<item itemtype="Connector" uid="Connector-216" startpinid="mega48-116-PORTB5" endpinid="Tunnel-73-pin" pointList="-580,-68,-564,-68" />

<item itemtype="Connector" uid="Connector-219" startpinid="Tunnel-76-pin" endpinid="mega48-116-PORTB2" pointList="-564,-92,-580,-92" />

<item itemtype="Connector" uid="Connector-220" startpinid="Tunnel-75-pin" endpinid="mega48-116-PORTB3" pointList="-564,-84,-580,-84" />

<item itemtype="Connector" uid="Connector-221" startpinid="mega48-116-PORTB4" endpinid="Tunnel-74-pin" pointList="-580,-76,-564,-76" />

<item itemtype="Connector" uid="Connector-223" startpinid="mega48-118-PORTV0" endpinid="Node-119-1" pointList="-436,-28,-444,-28,-444,-36" />

<item itemtype="Connector" uid="Connector-224" startpinid="Tunnel-62-pin" endpinid="Node-119-0" pointList="-452,-36,-444,-36" />

<item itemtype="Connector" uid="Connector-225" startpinid="Node-119-2" endpinid="mega48-118-PORTV1" pointList="-444,-36,-436,-36" />

<item itemtype="Connector" uid="Connector-226" startpinid="mega48-118-PORTB5" endpinid="Tunnel-78-pin" pointList="-380,-68,-364,-68" />

<item itemtype="Connector" uid="Connector-227" startpinid="Tunnel-79-pin" endpinid="mega48-118-PORTB4" pointList="-364,-76,-380,-76" />

<item itemtype="Connector" uid="Connector-228" startpinid="mega48-118-PORTB3" endpinid="Tunnel-80-pin" pointList="-380,-84,-364,-84" />

<item itemtype="Connector" uid="Connector-229" startpinid="mega48-118-PORTB2" endpinid="Tunnel-77-pin" pointList="-380,-92,-364,-92" />

<item itemtype="Connector" uid="Connector-231" startpinid="mega48-120-PORTV0" endpinid="Node-124-1" pointList="-236,-28,-244,-28,-244,-36" />

<item itemtype="Connector" uid="Connector-232" startpinid="Tunnel-64-pin" endpinid="Node-124-0" pointList="-252,-36,-244,-36" />

<item itemtype="Connector" uid="Connector-233" startpinid="Node-124-2" endpinid="mega48-120-PORTV1" pointList="-244,-36,-236,-36" />

<item itemtype="Connector" uid="Connector-234" startpinid="Tunnel-82-pin" endpinid="mega48-120-PORTB5" pointList="-164,-68,-180,-68" />

<item itemtype="Connector" uid="Connector-235" startpinid="mega48-120-PORTB4" endpinid="Tunnel-83-pin" pointList="-180,-76,-164,-76" />

<item itemtype="Connector" uid="Connector-236" startpinid="Tunnel-84-pin" endpinid="mega48-120-PORTB3" pointList="-164,-84,-180,-84" />

<item itemtype="Connector" uid="Connector-237" startpinid="mega48-120-PORTB2" endpinid="Tunnel-81-pin" pointList="-180,-92,-164,-92" />

<item itemtype="Connector" uid="Connector-239" startpinid="mega48-121-PORTV0" endpinid="Node-125-1" pointList="-636,164,-644,164,-644,156" />

<item itemtype="Connector" uid="Connector-240" startpinid="Tunnel-66-pin" endpinid="Node-125-0" pointList="-652,156,-644,156" />

<item itemtype="Connector" uid="Connector-241" startpinid="Node-125-2" endpinid="mega48-121-PORTV1" pointList="-644,156,-636,156" />

<item itemtype="Connector" uid="Connector-242" startpinid="mega48-121-PORTB5" endpinid="Tunnel-86-pin" pointList="-580,124,-564,124" />

<item itemtype="Connector" uid="Connector-243" startpinid="Tunnel-87-pin" endpinid="mega48-121-PORTB4" pointList="-564,116,-580,116" />

<item itemtype="Connector" uid="Connector-244" startpinid="mega48-121-PORTB3" endpinid="Tunnel-88-pin" pointList="-580,108,-564,108" />

<item itemtype="Connector" uid="Connector-245" startpinid="Tunnel-85-pin" endpinid="mega48-121-PORTB2" pointList="-564,100,-580,100" />

<item itemtype="Connector" uid="Connector-247" startpinid="mega48-122-PORTV0" endpinid="Node-126-1" pointList="-436,164,-444,164,-444,156" />

<item itemtype="Connector" uid="Connector-248" startpinid="Tunnel-67-pin" endpinid="Node-126-0" pointList="-452,156,-444,156" />

<item itemtype="Connector" uid="Connector-249" startpinid="Node-126-2" endpinid="mega48-122-PORTV1" pointList="-444,156,-436,156" />

<item itemtype="Connector" uid="Connector-250" startpinid="mega48-122-PORTB5" endpinid="Tunnel-90-pin" pointList="-380,124,-364,124" />

<item itemtype="Connector" uid="Connector-251" startpinid="Tunnel-91-pin" endpinid="mega48-122-PORTB4" pointList="-364,116,-380,116" />

<item itemtype="Connector" uid="Connector-252" startpinid="mega48-122-PORTB3" endpinid="Tunnel-92-pin" pointList="-380,108,-364,108" />

<item itemtype="Connector" uid="Connector-253" startpinid="Tunnel-89-pin" endpinid="mega48-122-PORTB2" pointList="-364,100,-380,100" />

<item itemtype="Connector" uid="Connector-255" startpinid="mega48-123-PORTV0" endpinid="Node-127-1" pointList="-236,164,-244,164,-244,156" />

<item itemtype="Connector" uid="Connector-256" startpinid="Tunnel-68-pin" endpinid="Node-127-0" pointList="-252,156,-244,156" />

<item itemtype="Connector" uid="Connector-257" startpinid="Node-127-2" endpinid="mega48-123-PORTV1" pointList="-244,156,-236,156" />

<item itemtype="Connector" uid="Connector-258" startpinid="Tunnel-94-pin" endpinid="mega48-123-PORTB5" pointList="-164,124,-180,124" />

<item itemtype="Connector" uid="Connector-259" startpinid="mega48-123-PORTB4" endpinid="Tunnel-95-pin" pointList="-180,116,-164,116" />

<item itemtype="Connector" uid="Connector-260" startpinid="Tunnel-96-pin" endpinid="mega48-123-PORTB3" pointList="-164,108,-180,108" />

<item itemtype="Connector" uid="Connector-261" startpinid="mega48-123-PORTB2" endpinid="Tunnel-93-pin" pointList="-180,100,-164,100" />

</circuit>

[/spoiler]

Hello,

I am trying to create a program in which seven microcontrollers communicate with each other using SPI. One is master and six are slaves. I used a classic configuration where MISO MOSI and SCK are shared and SS pins are separate for each microcontroller.

Data sending works fine. I send numbers from 0 to 255 which are displayed on the D port of the slave device. For control I send the same data back to the master device. But the MISO pin fights with the other MISO pins.
First I used ATmega8 as slave but in datasheet on page 125 (datasheet) I found that after SS is high all SPI pins except MISO are inputs.

So I used as slave ATmega48 where in datasheet on page 174 (datasheet) says that after SS is high all SPI pins are inputs.
Despite this, the MISO pins seem to interfere with each other.

Can you help me with this?

Thank you and have a nice day.

Regards
tomas714

PS: I don't know why but the attached files are not displayed. I tried to edit the post but it doesn't work.

master.hex

:100000000C9434000C9498000C9498000C94980074
:100010000C9498000C9498000C9498000C94980000
:100020000C9498000C9498000C9498000C949800F0
:100030000C9498000C9498000C9498000C949800E0
:100040000C9498000C9498000C9498000C949800D0
:100050000C9498000C9498000C9498000C949800C0
:100060000C9498000C94980011241FBECFEFD8E098
:10007000DEBFCDBF0E947F000C948A00F894FFCFB2
:100080004BB121E030E0F90102C0EE0FFF1F8A956D
:10009000E2F7CF012E2F209542234BB96EBD0DB450
:0E00A00007FEFDCF9BB1892B8BB98EB508955D
:1000AE008AB18F638AB98BB18F638BB9239A259AE4
:1000BE008CB580648CBD8CB580618CBD8CB5816037
:0A00CE008CBD8DB581608DBD0895D5
:1000D800CF93DF93D0E00AC06D2F8C2F0E94400091
:1000E800CF5FC630C9F7DF5FDF3F11F0C0E0F4CF64
:0600F800DF91CF91089595
:1000FE008DB79EB701960E9495008DB79EB701965B
:06010E000E946C00FACF14
:10011400EC010E949D000E949C00CE010E949E0062
:06012400CE010E949A00CA
:06012A000E945700089539
:040130000C9400002B
:040134000E943E00E7
:02013800089528
:02013A00089526
:02013C00089524
:00000001FF

slave.hex

:1000000019C04DC04CC04BC04AC049C048C047C0D1
:1000100046C045C044C043C042C041C040C03FC0CC
:100020003EC03DC03CC03BC03AC039C038C037C0FC
:1000300036C035C011241FBECFEFD2E0DEBFCDBF2A
:080040000ED01DC0F894FFCFA3
:10004800249A8CB580648CBD8CB581608CBD8DB5CF
:0600580081608DBD0895DA
:10005E008DB79EB701961AD08DB79EB7019601D077
:02006E00FBCFC6
:0E0070008FEF8AB90BD08BB98BB10DD00895EC
:0E007E00EC0110D00ED0CE010ED0CE010DD070
:0A008C000DB407FEFDCF8EB50895F8
:040096008EBD08957E
:04009A00D6DF089510
:02009E00B0CFE1
:0200A0000895C1
:0200A2000895BF
:0200A4000895BD
:0200A600CEDFAB
:00000001FF

simulide.sim1

</circuit>

#2 · October 19, 2024, 4:23 am

Hi.

You are right, the MISO pin is not handled properly in slave mode. Thanks for reporting.
Fixed at 1.1.0 Rev 2007.

tomas714 has reacted to this post.