Are you directly driving those LEDs? The current (per userport output) should not exceed 1mA, therefore you should use some sort of driver (transistor, ..). Otherwise you risk blowing up your poor CIA chip.
0:37 to 0:40: Pause for typing this programm in your C64 :) There excist a shematic that uses 74LS257 or something else incl. some resistors. U got this shematic? Would look nice to use 74LS257 and my Oceanic via parallel cable at the same time. Or would it work with your solution too?
0:33 Your time stamp doesn't work. Maybe it was made too long before TH-cam made clickable. I chose 33 seconds to let the user hear the following message.
Hi, I am researching some way I can hook a PC to a C64 and transmit data back and forth when I came across your nice simple project showing how the user port is used. I see the address at 56579 is where you decide if each pin is read or write so poking this to 0 should enable reading from it too i guess? But for connecting this to a PC I was thinking something like the Atmega32u4 would work? Any idea what kind of electronics would be needed between the Atmega32u4 and the C64? The Atmega32u4 would get power from the USB port but would one need optocouplers to actually send the data to and from the C64 user port, or could one just wire directly between the pins on the Atmega32u4 to the C64 user port?
+64jcl If the Atmega is running at 5V then you should be able to hook it up directly to the user port pins; otherwise you may need to convert. I've used one of these to hook a C64 up to a 3.3V device before: www.adafruit.com/products/757
@Dwight A. Spencer , been a while since I posted this. I got it working just fine on the userport and the transfer rates is many orders of mangnitude faster than the RS232 of the C64 as I can write full bytes directly to the port. I have since dabbled a bit with the new wifi modems you can get for the C64 as well and that uses the simpler RS232 implementation although anyone wanting to test that out must know if they use the Kernal for that there is a bug in the timing tables for PAL machines so you can only get it working up to 1200 baud. With the fix 2400 baud works fine although a custom implementation that bypasses the whole Kernal you can get 9600 baud working as well.
Yes, it is possible to use as input lines. POKE 56579,255 makes all 8 lines as outputs. POKE 56579,0 makes all lines as inputs. You can combine lines as you wish.
Are you directly driving those LEDs? The current (per userport output) should not exceed 1mA, therefore you should use some sort of driver (transistor, ..). Otherwise you risk blowing up your poor CIA chip.
Hello
I would like to control 2 outputs via 2 5Volts input signals.
Can you help me?
0:37 to 0:40: Pause for typing this programm in your C64 :)
There excist a shematic that uses 74LS257 or something else incl. some resistors. U got this shematic? Would look nice to use 74LS257 and my Oceanic via parallel cable at the same time. Or would it work with your solution too?
0:33 Your time stamp doesn't work. Maybe it was made too long before TH-cam made clickable.
I chose 33 seconds to let the user hear the following message.
Hi, I am researching some way I can hook a PC to a C64 and transmit data back and forth when I came across your nice simple project showing how the user port is used. I see the address at 56579 is where you decide if each pin is read or write so poking this to 0 should enable reading from it too i guess? But for connecting this to a PC I was thinking something like the Atmega32u4 would work? Any idea what kind of electronics would be needed between the Atmega32u4 and the C64? The Atmega32u4 would get power from the USB port but would one need optocouplers to actually send the data to and from the C64 user port, or could one just wire directly between the pins on the Atmega32u4 to the C64 user port?
+64jcl If the Atmega is running at 5V then you should be able to hook it up directly to the user port pins; otherwise you may need to convert. I've used one of these to hook a C64 up to a 3.3V device before: www.adafruit.com/products/757
@Dwight A. Spencer , been a while since I posted this. I got it working just fine on the userport and the transfer rates is many orders of mangnitude faster than the RS232 of the C64 as I can write full bytes directly to the port. I have since dabbled a bit with the new wifi modems you can get for the C64 as well and that uses the simpler RS232 implementation although anyone wanting to test that out must know if they use the Kernal for that there is a bug in the timing tables for PAL machines so you can only get it working up to 1200 baud. With the fix 2400 baud works fine although a custom implementation that bypasses the whole Kernal you can get 9600 baud working as well.
Hey Chrsitopher, it works on both directions? Can you read TTL data?
Yes, it is possible to use as input lines. POKE 56579,255 makes all 8 lines as outputs. POKE 56579,0 makes all lines as inputs. You can combine lines as you wish.
Thank you!
Love this!!!!!!!
Great ...thanks