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IC7448 output 2.52 V max. rev 2278 (SOLVED)
#1 · May 29, 2024, 11:29 pm
Help! Is it a mistake of mine or a bug?
#2 · May 29, 2024, 11:30 pm
#define F_CPU 1000000UL
#include <avr/io.h>
#include <util/delay.h>
int main(void){
DDRD = 0x0F;
PORTD = 0x0F;
while(1){
for(char i=0x00; i<=0x0F; i++)
{
PORTD = i;
_delay_ms(1000);
}
}
}
#3 · May 29, 2024, 11:35 pm
AVR = attiny2313
COMPILE = avr-gcc -Wall -O3 -mmcu=$(AVR)
SOURCES = main.c
OUTPUT_HEX = main.hex
OBJECTS = $(patsubst %.c, %.o, $(SOURCES))
OUTPUT_ELF = $(patsubst %.hex, %.elf, $(OUTPUT_HEX))
all: $(OUTPUT_HEX)
%.o: %.c
$(COMPILE) -c $<
$(OUTPUT_HEX): $(OBJECTS)
$(COMPILE) $^ -o $(OUTPUT_ELF)
avr-objcopy -O ihex $(OUTPUT_ELF) $@
clean:
rm -f *.o *.elf *.hex
#4 · May 29, 2024, 11:37 pm
<circuit version="1.1.0-SR0" rev="2278" stepSize="1000000" stepsPS="1000000" NLsteps="100000" reaStep="1000000" animate="1" >
<item itemtype="Ground" CircId="Ground-1" mainComp="false" Show_id="false" Show_Val="false" Pos="124,-80" rotation="0" hflip="1" vflip="1" label="Ground-1" idLabPos="-16,8" labelrot="0" valLabPos="-16,20" valLabRot="0" />
<item itemtype="Seven Segment" CircId="Seven Segment-2" mainComp="false" Show_id="false" Show_Val="false" Pos="116,-136" rotation="0" hflip="1" vflip="1" label="Seven Segment-2" idLabPos="20,-44" labelrot="0" valLabPos="-16,20" valLabRot="0" Color="Yellow" NumDisplays="1" Vertical_Pins="false" CommonCathode="true" Threshold="2.4 V" MaxCurrent="20 mA" Resistance="1 Ω" />
<item itemtype="Led" CircId="Led-4" mainComp="false" Show_id="false" Show_Val="false" Pos="-32,-120" rotation="0" hflip="1" vflip="1" label="Led-4" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Color="Yellow" Grounded="true" Threshold="2.4 V" MaxCurrent="30 mA" Resistance="0.6 Ω" />
<item itemtype="MCU" CircId="tiny2313-5" mainComp="false" Show_id="true" Show_Val="false" Pos="-140,-172" rotation="0" hflip="-1" vflip="1" label="tiny2313-5" idLabPos="0,-20" labelrot="0" valLabPos="-16,20" valLabRot="0" Frequency="1 MHz" Program="ic7447.hex" Auto_Load="false" saveEepr="true" Logic_Symbol="false" Rst_enabled="false" Ext_Osc="false" Wdt_enabled="false" SerialMon="-1" />
<item itemtype="Rail" CircId="Rail-6" mainComp="false" ShowProp="Voltage" Show_id="false" Show_Val="true" Pos="16,-92" rotation="90" hflip="1" vflip="1" label="Rail-6" idLabPos="-5,-10" labelrot="-90" valLabPos="-12,6" valLabRot="-90" Voltage="5 V" />
<item itemtype="Resistor" CircId="Resistor-7" mainComp="false" ShowProp="Resistance" Show_id="false" Show_Val="true" Pos="-96,-140" rotation="0" hflip="1" vflip="1" label="Resistor-7" idLabPos="-16,-24" labelrot="0" valLabPos="-16,6" valLabRot="0" Resistance="100 Ω" />
<item itemtype="Resistor" CircId="Resistor-8" mainComp="false" ShowProp="Resistance" Show_id="false" Show_Val="true" Pos="-96,-160" rotation="0" hflip="1" vflip="1" label="Resistor-8" idLabPos="-16,-24" labelrot="0" valLabPos="-16,6" valLabRot="0" Resistance="100 Ω" />
<item itemtype="Led" CircId="Led-9" mainComp="false" Show_id="false" Show_Val="false" Pos="-32,-100" rotation="0" hflip="1" vflip="1" label="Led-9" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Color="Yellow" Grounded="true" Threshold="2.4 V" MaxCurrent="30 mA" Resistance="0.6 Ω" />
<item itemtype="Probe" CircId="Probe-11" mainComp="false" Show_id="false" Show_Val="true" Pos="-108,-192" rotation="-45" hflip="1" vflip="1" label="Probe-11" idLabPos="16,-16" labelrot="45" valLabPos="16,0" valLabRot="45" ShowVolt="true" Threshold="2.5 V" />
<item itemtype="Resistor" CircId="Resistor-12" mainComp="false" ShowProp="Resistance" Show_id="false" Show_Val="true" Pos="-96,-120" rotation="0" hflip="1" vflip="1" label="Resistor-12" idLabPos="-16,-24" labelrot="0" valLabPos="-16,6" valLabRot="0" Resistance="100 Ω" />
<item itemtype="Resistor" CircId="Resistor-13" mainComp="false" ShowProp="Resistance" Show_id="false" Show_Val="true" Pos="-96,-100" rotation="0" hflip="1" vflip="1" label="Resistor-13" idLabPos="-16,-24" labelrot="0" valLabPos="-16,6" valLabRot="0" Resistance="100 Ω" />
<item itemtype="Led" CircId="Led-14" mainComp="false" Show_id="false" Show_Val="false" Pos="-32,-140" rotation="0" hflip="1" vflip="1" label="Led-14" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Color="Yellow" Grounded="true" Threshold="2.4 V" MaxCurrent="30 mA" Resistance="0.6 Ω" />
<item itemtype="Subcircuit" CircId="74XX48-15" mainComp="false" Show_id="true" Show_Val="false" Pos="4,-168" rotation="0" hflip="1" vflip="1" label="74XX48-15" idLabPos="-6.3685,-13.98" labelrot="0" valLabPos="-16,20" valLabRot="0" Input_High_V="5 V" Input_Low_V="2.5 V" Input_Imped="1e+09 Ω" Out_High_V="5 V" Out_Low_V="0 V" Out_Imped="40 Ω" Tpd_ps="10 ns" Tr_ps="3 ns" Tf_ps="4 ns" Logic_Symbol="true" />
<item itemtype="Probe" CircId="Probe-17" mainComp="false" ShowProp="Threshold" Show_id="false" Show_Val="true" Pos="60,-176" rotation="-45" hflip="1" vflip="1" label="Probe-17" idLabPos="16,-16" labelrot="45" valLabPos="16,0" valLabRot="45" ShowVolt="true" Threshold="2.5 V" />
<item itemtype="Led" CircId="Led-20" mainComp="false" Show_id="false" Show_Val="false" Pos="-32,-160" rotation="0" hflip="1" vflip="1" label="Led-20" idLabPos="-16,-24" labelrot="0" valLabPos="-16,20" valLabRot="0" Color="Yellow" Grounded="true" Threshold="2.4 V" MaxCurrent="30 mA" Resistance="0.6 Ω" />
<item itemtype="ResistorDip" CircId="ResistorDip-21" mainComp="false" ShowProp="Resistance" Show_id="false" Show_Val="true" Pos="68,-136" rotation="0" hflip="1" vflip="1" label="ResistorDip-21" idLabPos="-24,-40" labelrot="0" valLabPos="4,-26" valLabRot="90" Resistance="100 Ω" Size="7" PullUp="false" PuVolt="5 V" />
<item itemtype="Node" CircId="Node-3" mainComp="false" Pos="-4,-120" />
<item itemtype="Node" CircId="Node-10" mainComp="false" Pos="-120,-156" />
<item itemtype="Node" CircId="Node-16" mainComp="false" Pos="-124,-148" />
<item itemtype="Node" CircId="Node-18" mainComp="false" Pos="-4,-112" />
<item itemtype="Node" CircId="Node-19" mainComp="false" Pos="-120,-124" />
<item itemtype="Node" CircId="Node-22" mainComp="false" Pos="-128,-116" />
<item itemtype="Connector" uid="Connector-1" startpinid="Node-3-2" endpinid="74XX48-15-RBI" pointList="-4,-120,-4,-120" />
<item itemtype="Connector" uid="Connector-2" startpinid="ResistorDip-21-resistor4-ePin9" endpinid="Seven Segment-2-pin_e" pointList="84,-128,92,-128" />
<item itemtype="Connector" uid="Connector-3" startpinid="ResistorDip-21-resistor4-ePin8" endpinid="74XX48-15-e" pointList="52,-128,44,-128" />
<item itemtype="Connector" uid="Connector-4" startpinid="tiny2313-5-PORTD0" endpinid="Node-10-0" pointList="-132,-156,-120,-156" />
<item itemtype="Connector" uid="Connector-5" startpinid="74XX48-15-b" endpinid="ResistorDip-21-resistor1-ePin2" pointList="44,-152,52,-152" />
<item itemtype="Connector" uid="Connector-6" startpinid="ResistorDip-21-resistor1-ePin3" endpinid="Seven Segment-2-pin_b" pointList="84,-152,92,-152" />
<item itemtype="Connector" uid="Connector-7" startpinid="Node-16-2" endpinid="Resistor-7-lPin" pointList="-124,-148,-112,-148,-112,-140" />
<item itemtype="Connector" uid="Connector-8" startpinid="Node-19-2" endpinid="tiny2313-5-PORTD2" pointList="-120,-124,-132,-124" />
<item itemtype="Connector" uid="Connector-9" startpinid="74XX48-15-BI/RBO" endpinid="Node-3-0" pointList="-4,-128,-4,-120" />
<item itemtype="Connector" uid="Connector-10" startpinid="74XX48-15-d" endpinid="ResistorDip-21-resistor3-ePin6" pointList="44,-136,52,-136" />
<item itemtype="Connector" uid="Connector-11" startpinid="Node-10-1" endpinid="74XX48-15-A" pointList="-120,-156,-120,-172,-16,-172,-16,-160,-4,-160" />
<item itemtype="Connector" uid="Connector-12" startpinid="ResistorDip-21-resistor6-ePin13" endpinid="Seven Segment-2-pin_g" pointList="84,-112,92,-112" />
<item itemtype="Connector" uid="Connector-13" startpinid="Node-10-2" endpinid="Resistor-8-lPin" pointList="-120,-156,-112,-156,-112,-160" />
<item itemtype="Connector" uid="Connector-14" startpinid="Node-18-1" endpinid="Rail-6-outnod" pointList="-4,-112,-4,-76,16,-76" />
<item itemtype="Connector" uid="Connector-15" startpinid="Resistor-13-rPin" endpinid="Led-9-lPin" pointList="-80,-100,-48,-100" />
<item itemtype="Connector" uid="Connector-16" startpinid="Node-19-1" endpinid="74XX48-15-C" pointList="-120,-124,-120,-88,-16,-88,-16,-144,-4,-144" />
<item itemtype="Connector" uid="Connector-17" startpinid="Resistor-12-rPin" endpinid="Led-4-lPin" pointList="-80,-120,-48,-120" />
<item itemtype="Connector" uid="Connector-18" startpinid="Node-16-1" endpinid="74XX48-15-B" pointList="-124,-148,-124,-176,-12,-176,-12,-152,-4,-152" />
<item itemtype="Connector" uid="Connector-19" startpinid="Resistor-12-lPin" endpinid="Node-19-0" pointList="-112,-120,-112,-124,-120,-124" />
<item itemtype="Connector" uid="Connector-20" startpinid="Resistor-13-lPin" endpinid="Node-22-0" pointList="-112,-100,-112,-116,-128,-116" />
<item itemtype="Connector" uid="Connector-21" startpinid="Node-22-1" endpinid="74XX48-15-D" pointList="-128,-116,-128,-84,-8,-84,-8,-136,-4,-136" />
<item itemtype="Connector" uid="Connector-22" startpinid="Resistor-7-rPin" endpinid="Led-14-lPin" pointList="-80,-140,-48,-140" />
<item itemtype="Connector" uid="Connector-23" startpinid="ResistorDip-21-resistor0-ePin0" endpinid="74XX48-15-a" pointList="52,-160,44,-160" />
<item itemtype="Connector" uid="Connector-24" startpinid="Node-22-2" endpinid="tiny2313-5-PORTD3" pointList="-128,-116,-132,-116" />
<item itemtype="Connector" uid="Connector-25" startpinid="ResistorDip-21-resistor6-ePin12" endpinid="74XX48-15-g" pointList="52,-112,44,-112" />
<item itemtype="Connector" uid="Connector-26" startpinid="tiny2313-5-PORTD1" endpinid="Node-16-0" pointList="-132,-148,-124,-148" />
<item itemtype="Connector" uid="Connector-27" startpinid="Node-18-2" endpinid="74XX48-15-LT" pointList="-4,-112,-4,-112" />
<item itemtype="Connector" uid="Connector-28" startpinid="Seven Segment-2-pin_f" endpinid="ResistorDip-21-resistor5-ePin11" pointList="92,-120,84,-120" />
<item itemtype="Connector" uid="Connector-29" startpinid="ResistorDip-21-resistor2-ePin4" endpinid="74XX48-15-c" pointList="52,-144,44,-144" />
<item itemtype="Connector" uid="Connector-30" startpinid="ResistorDip-21-resistor0-ePin1" endpinid="Seven Segment-2-pin_a" pointList="84,-160,92,-160" />
<item itemtype="Connector" uid="Connector-31" startpinid="Seven Segment-2-pin_commona" endpinid="Ground-1-Gnd" pointList="124,-104,124,-96" />
<item itemtype="Connector" uid="Connector-32" startpinid="74XX48-15-f" endpinid="ResistorDip-21-resistor5-ePin10" pointList="44,-120,52,-120" />
<item itemtype="Connector" uid="Connector-33" startpinid="Node-3-1" endpinid="Node-18-0" pointList="-4,-120,-4,-112" />
<item itemtype="Connector" uid="Connector-34" startpinid="Seven Segment-2-pin_c" endpinid="ResistorDip-21-resistor2-ePin5" pointList="92,-144,84,-144" />
<item itemtype="Connector" uid="Connector-35" startpinid="Resistor-8-rPin" endpinid="Led-20-lPin" pointList="-80,-160,-48,-160" />
<item itemtype="Connector" uid="Connector-36" startpinid="Seven Segment-2-pin_d" endpinid="ResistorDip-21-resistor3-ePin7" pointList="92,-136,84,-136" />
</circuit>
#5 · May 31, 2024, 9:38 am
Hi, what is exactly the problem?
#6 · May 31, 2024, 9:17 pm
Why is the voltage output of the 7448 only 2.52V? (see first post)
it should be similar to the output of the 2313 which is 4.26V.
Or where did I go wrong?
#7 · June 1, 2024, 6:37 am
Edit "74xx48.sim1" by modifying the resistors of all outputs from 2k to 100 ohms and remove the series resistors that you have on the display. The 74xx48 is in the data/ICs directory.
The proposed idea is a "simple" solution to see that the scheme works with the 74xx48 BCD decoder and the common cathode 7 Segment LED display, but in the 74xx48 commercial IC the seven outputs "a" to "f" are OPEN COLLECTOR TTL with an internal pullup resistor of 2 kohms at +5v. For the screen to illuminate regularly, the high level current must be reinforced by placing an external resistor of about 150 ohms at +5V in each of them. Another solution, which involves adding more hardware, is to add a non-inverting driver on each of the outputs. This solution allows the option of using other higher power displays, adding resistors in series with the segments that limit the current in this case.
Lazlo_lozla has reacted to this post.
Lazlo_lozla
#8 · June 1, 2024, 5:43 pm
I made the changes and the 7 segment display illuminated better. thanks!