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Re: PiStorm
Stupid question, but how is an emulated processor on a real QL going to be better than an emulated processor in sQLux or similar? Since the emulated Io is superior to genuine IO in every way, couldn't we just make a QL-fitting carrier board for a CM4 for the QL case?
Re: 4864 DRAM
I dug through my notes and found the following: D06- had NEC UPD4164C-3 (seen once) D06- had Hitachi HM4864P2 D09- had Siemens HYB4164P2 D09- had TI TMS4164-15NL (most common) D09- had Mostek MK4564-15 S18- had TI TMS4164-12NL Others I haven't seen but listed in the service manual include MCM6665AP1...
- Tue Apr 09, 2024 11:10 pm
- Forum: Prospective Members
- Topic: Alas...
- Replies: 0
- Views: 72
Alas...
I think we can lay this one to rest now.
- Tue Apr 09, 2024 10:35 pm
- Forum: Hardware
- Topic: Switching Regulator?
- Replies: 37
- Views: 2271
Re: Switching Regulator?
Interesting conversation to catch up on. 7805 is a very inefficient analog regulator and that inefficiency comes out as heat. Often 60-70% efficient, depending on the input/output voltage. Buck regulators are switching 'digital' regulators [1] that make a lot of switching noise but are very efficien...
- Tue Apr 09, 2024 9:56 pm
- Forum: Hardware
- Topic: Serial port confusion.
- Replies: 18
- Views: 3872
Re: Serial port confusion.
Actually, Sinclair's solution was a good idea of having a DTE and a DCE configured serial port because it avoids having an external NULL modem gender changer because the conversion is builtin to the QL. They made up for it with the bad idea that received information from both sockets goes to a sing...
- Tue Apr 09, 2024 9:52 pm
- Forum: Hardware
- Topic: FPGA replacment for the ZX8301 ULA and more
- Replies: 254
- Views: 99137
Re: FPGA replacment for the ZX8301 ULA and more
Yeah, those red sockets are junk. I have had to replace dozens of them as they often fall apart if the CPU is stuck in them. Any time I installed an internal memory expansion in a QL at Sandy and it had a red socket, I'd fire up the weller first just in case. On my multitude of QLs, if I see a red s...
Re: PiStorm
The PiStorm signal transitions are incredibly quick, and play absolute mayhem with the QL. The PiStorm can function in a Gold Card if the onboard DRAM is removed and the refresh signal used by INGOT is inhibited. However, external signals would need conditioning to reduce their slew rate. The SGC cl...
- Tue Apr 09, 2024 9:06 pm
- Forum: Hardware
- Topic: USB Keyboard IF
- Replies: 38
- Views: 8292
Re: USB Keyboard IF
Also its a mystery that the QL has a 9x11 Matrix, the 8049 IPC only supports 8x8 Matrix. The CTRL, ALT and SHIFT keys are on their own line separate from any other keys, so pressing them and two other keys does not create a ghost click on the 4th corner. This adds one line on one axis of the table ...
Re: 4864 DRAM
The RAM in the QL was the absolute least they could get away with. Everything is marginal. With the incredibly poor power and debounce practices used, the QL seems to spend almost all its life only just working. Some early FB QLs had -200 DRAM, but they quickly switched to -150 and some of the very ...
- Tue Apr 09, 2024 7:41 pm
- Forum: Hardware
- Topic: FPGA replacment for the ZX8301 ULA and more
- Replies: 254
- Views: 99137
Re: FPGA replacment for the ZX8301 ULA and more
I looked at this project on Hackaday and it is quite interesting. On the buffer, it would help to connect all unused inputs to ground or +5V. Between the buffer and the monitor connected pins of the 8301 socket, it would offer extra protection to add 5.1V zener diodes to ground. Apart from that, eve...