Post by mike351 on May 5, 2018 11:44:42 GMT
Hello modders!
If you want to do any major customisation to the64mini one of the first things you will need to do is add the UART connector so you can gain access to the internal software. You'll need basic soldering skills and a simple soldering iron that you can get from almost any electronics store. I wouldn't recommend anything more than a 30w iron otherwise you might damage the delicate copper tracks. Soldering takes a bit to perfect, all I can say is, always dab a little solder on the tip first, make sure the tip sits on both the pin you are soldering and the pad you want the solder to flow on, feed the solder on steady and only just enough to make the bond and I always try to make sure this action is done in no more than 5 seconds or you may damage the delicate copper tracks.
What you'll need:
USB to 3.3v TTL RS232 adaptor. It MUST use 3.3v for the Tx line. Be careful as some are 5v and may damage your mini! Use a multimeter to confirm. I bought this from Ebay
Soldering Iron with fine pointed tip (fine chisel will also do)
Multimeter (Optional but recommended to test the Tx line of your adaptor)
Solder (60/40 and thin diameter, maybe .7 or so)
Header pins that you can snap off. This is what I bought and snapped off a row of four. Header Pins
Start..
Open up the 64 Mini by turning it over and peeling off the four rubber feet, remove exposed screws.
Gently pull the two connectors off the pcb that go to the power led and the switch on the bottom of the case.
Undo the screws that hold the pcb to the bottom section of the case.
Locate the four through holes on the pcb, just near the A20 chip, these connections are for the serial uart, and it is here you will solder on to the short ends of your pcb connector that will be sticking through.
Place the longer section of the four pcb pins on the side that has no chips on it and solder in place. Once finished, put the pcb back in place and put the screws back in.
Following the instructions that came with your USB to TTL converter, install drivers (if required) and connect to a free USB port, and the serial connections to the uart pins you just installed. You will need to make the connections like this:
64Mini UART / USB TTL Adapter
GND GND
Tx Rx
Rx Tx
3.3v None
Download PuTTY or some other serial terminal program and set the baud rate for 115200 and data format 8,n,1. Com port will be dependant on your particular setup, mine was Com3 according to device manager.
Make sure you select 'Serial' so you can enter these values in.
Connect your 64mini to hdmi and power. If you have done everything correctly you should be seeing the console output in the terminal program window, congratulations! You can move to the next section. If not, check that the connections are correct (ie that you haven’t connected tx to tx and rx to rx), check that your terminal program is configured for the correct com port.
A basic check you can do is to disconnect your serial cable from the mini and connect its Tx and Rx lines together and then type on your keyboard. You should see what you type on the keyboard echoed in the terminal window. If not, you need to double check those comms settings.
And that's it. With any luck you now have access to the internal operating system and software of your 64mini.
In my next post i'll cover how you can replace the kernal and drive roms with JiffyDOS so loading those programs from your USB will be nice and fast!
Mike
If you want to do any major customisation to the64mini one of the first things you will need to do is add the UART connector so you can gain access to the internal software. You'll need basic soldering skills and a simple soldering iron that you can get from almost any electronics store. I wouldn't recommend anything more than a 30w iron otherwise you might damage the delicate copper tracks. Soldering takes a bit to perfect, all I can say is, always dab a little solder on the tip first, make sure the tip sits on both the pin you are soldering and the pad you want the solder to flow on, feed the solder on steady and only just enough to make the bond and I always try to make sure this action is done in no more than 5 seconds or you may damage the delicate copper tracks.
What you'll need:
USB to 3.3v TTL RS232 adaptor. It MUST use 3.3v for the Tx line. Be careful as some are 5v and may damage your mini! Use a multimeter to confirm. I bought this from Ebay
Soldering Iron with fine pointed tip (fine chisel will also do)
Multimeter (Optional but recommended to test the Tx line of your adaptor)
Solder (60/40 and thin diameter, maybe .7 or so)
Header pins that you can snap off. This is what I bought and snapped off a row of four. Header Pins
Start..
Open up the 64 Mini by turning it over and peeling off the four rubber feet, remove exposed screws.
Gently pull the two connectors off the pcb that go to the power led and the switch on the bottom of the case.
Undo the screws that hold the pcb to the bottom section of the case.
Locate the four through holes on the pcb, just near the A20 chip, these connections are for the serial uart, and it is here you will solder on to the short ends of your pcb connector that will be sticking through.
Place the longer section of the four pcb pins on the side that has no chips on it and solder in place. Once finished, put the pcb back in place and put the screws back in.
Following the instructions that came with your USB to TTL converter, install drivers (if required) and connect to a free USB port, and the serial connections to the uart pins you just installed. You will need to make the connections like this:
64Mini UART / USB TTL Adapter
GND GND
Tx Rx
Rx Tx
3.3v None
Download PuTTY or some other serial terminal program and set the baud rate for 115200 and data format 8,n,1. Com port will be dependant on your particular setup, mine was Com3 according to device manager.
Make sure you select 'Serial' so you can enter these values in.
Connect your 64mini to hdmi and power. If you have done everything correctly you should be seeing the console output in the terminal program window, congratulations! You can move to the next section. If not, check that the connections are correct (ie that you haven’t connected tx to tx and rx to rx), check that your terminal program is configured for the correct com port.
A basic check you can do is to disconnect your serial cable from the mini and connect its Tx and Rx lines together and then type on your keyboard. You should see what you type on the keyboard echoed in the terminal window. If not, you need to double check those comms settings.
And that's it. With any luck you now have access to the internal operating system and software of your 64mini.
In my next post i'll cover how you can replace the kernal and drive roms with JiffyDOS so loading those programs from your USB will be nice and fast!
Mike
