Hello Velesoft. I didn't want you to think that I haven't bothered with this. My father in Law is away in Spain at the moment, looks like the soonest I can get this done will be June sometime, maybe even July or August. I will definitely ask him to do it when I next see him. I am very grateful that you have taken the trouble to work this out for me.
Would both versions of the modification work equally well? Or would you recommend one more than the other?
I have just spent an hour or so investigating the problems with using Joystick interfaces with the DivIDE Plus.
If I run games from FATware, a wide variety of interfaces work, although one or two appear to act as if the joystick is stuck in one direction (even when others by the same manufacturer and in the same case work fine).
If I load games under ResiDOS, the only joystick interfaces I could get to work are DK'Tronics interfaces (both single and dual port). All the others prevent ResiDOS from even installing (it reports no memory found).
I wonder why?
I have emailed Garry in case there is anything which could be done in ResiDOS itself.
I have just spent an hour or so investigating the problems with using Joystick interfaces with the DivIDE Plus.
If I run games from FATware, a wide variety of interfaces work, although one or two appear to act as if the joystick is stuck in one direction (even when others by the same manufacturer and in the same case work fine).
If I load games under ResiDOS, the only joystick interfaces I could get to work are DK'Tronics interfaces (both single and dual port). All the others prevent ResiDOS from even installing (it reports no memory found).
I wonder why?
I have emailed Garry in case there is anything which could be done in ResiDOS itself.
DIVIDE PLUS use extra port 23 for features/paging/MB02/RESIDOS....
BIN adress 23 is: 00010111 (A7-A0). As you can see - adress A7-A5=0 and this is problem. Adress of kempston port is 31 : BIN 00011111 (A7-A0). Kempston joystick port decoders accept only A5 or A7-A5 and need this adress lines in log.0 value. Other adress lines are ignored. Then any access to port 23 is for kempston same as access to port 31. DIVIDE PLUS will not work with all kempston joystick interfaces with absent signal RD. If RD is not used then kempston interface after IN 31 or OUT 31 send to data bus joy state. Yes, also after writing to joystick port this interface return data = data collision on zx bus ! Read and write to joy port is same !!! And all this interfaces use also uncomplette ports adressation then detect access to port 23 as access to joy port (A7-A5 is on this adress lines in same value = same port).
Result: after any OUT 23,xx external kempston joystick interface (without RD signal) send parallel to data bus joy state and data bus will very unstable - to port 23 is writed bad values....
Exist some different ways for fix this problem:
- change port 23 on DIVIDE PLUS
- add RD signal to port decoder on joy interface
- connect data bus between DIVIDE PLUS board and new ZX BUS connector via resistor 150 Ohm (8x resistor on D0-D7) - it's easy and usable and data bus is protected !!! All joystick inerfaces will work without modification !
It's modified photo of DIVIDE PLUS with new ZX-BUS connector with SMD resistors on data bus:
And it's original photo (contacts on zx-bus are short = soldering of resistors can be problematic. Absent green line (mask) after resistor (protection for clear soldering):
1) interrupt red wire
2) add two diodes and one resistor
Next variant with chip 74LS32 coming soon...
Hello Velesoft. At long last I will soon be in a position to complete this mod that you kindly suggested. I am ready to buy the resistors and diodes, what type of diodes should I buy? I presume the only rating that the resistor has is 1K Ohm?
If you could point me in the right direction to replace the 7805 regulator in a issue 3 48K spectrum, I would also be very grateful.
Hello Velesoft. At long last I will soon be in a position to complete this mod that you kindly suggested. I am ready to buy the resistors and diodes, what type of diodes should I buy? I presume the only rating that the resistor has is 1K Ohm?
- universal diodes 1N4148 or similar
- any resistor 1K Ohm
Comments
Mine has the missing line too. Only two ic's has my PCB:
SN74LS00N
74LS240N
Micky
Hello Velesoft. I didn't want you to think that I haven't bothered with this. My father in Law is away in Spain at the moment, looks like the soonest I can get this done will be June sometime, maybe even July or August. I will definitely ask him to do it when I next see him. I am very grateful that you have taken the trouble to work this out for me.
Would both versions of the modification work equally well? Or would you recommend one more than the other?
both work equally
OK thanks velesoft.
SN74LS00N
74LS240N
Same soldering as in the picture?
Micky
If I run games from FATware, a wide variety of interfaces work, although one or two appear to act as if the joystick is stuck in one direction (even when others by the same manufacturer and in the same case work fine).
If I load games under ResiDOS, the only joystick interfaces I could get to work are DK'Tronics interfaces (both single and dual port). All the others prevent ResiDOS from even installing (it reports no memory found).
I wonder why?
I have emailed Garry in case there is anything which could be done in ResiDOS itself.
www.rwapsoftware.co.uk
www.sellmyretro.com
DIVIDE PLUS use extra port 23 for features/paging/MB02/RESIDOS....
BIN adress 23 is: 00010111 (A7-A0). As you can see - adress A7-A5=0 and this is problem. Adress of kempston port is 31 : BIN 00011111 (A7-A0). Kempston joystick port decoders accept only A5 or A7-A5 and need this adress lines in log.0 value. Other adress lines are ignored. Then any access to port 23 is for kempston same as access to port 31. DIVIDE PLUS will not work with all kempston joystick interfaces with absent signal RD. If RD is not used then kempston interface after IN 31 or OUT 31 send to data bus joy state. Yes, also after writing to joystick port this interface return data = data collision on zx bus ! Read and write to joy port is same !!! And all this interfaces use also uncomplette ports adressation then detect access to port 23 as access to joy port (A7-A5 is on this adress lines in same value = same port).
Result: after any OUT 23,xx external kempston joystick interface (without RD signal) send parallel to data bus joy state and data bus will very unstable - to port 23 is writed bad values....
Exist some different ways for fix this problem:
- change port 23 on DIVIDE PLUS
- add RD signal to port decoder on joy interface
- connect data bus between DIVIDE PLUS board and new ZX BUS connector via resistor 150 Ohm (8x resistor on D0-D7) - it's easy and usable and data bus is protected !!! All joystick inerfaces will work without modification !
It's modified photo of DIVIDE PLUS with new ZX-BUS connector with SMD resistors on data bus:
And it's original photo (contacts on zx-bus are short = soldering of resistors can be problematic. Absent green line (mask) after resistor (protection for clear soldering):
Hello Velesoft. At long last I will soon be in a position to complete this mod that you kindly suggested. I am ready to buy the resistors and diodes, what type of diodes should I buy? I presume the only rating that the resistor has is 1K Ohm?
If you could point me in the right direction to replace the 7805 regulator in a issue 3 48K spectrum, I would also be very grateful.
- universal diodes 1N4148 or similar
- any resistor 1K Ohm
Thanks Velesoft, I'll let you know how we get on.