Search found 956 matches

by dp11
Thu Oct 17, 2019 7:53 pm
Forum: programming
Topic: Mode 7 flip between pages
Replies: 12
Views: 766

Re: Mode 7 flip between pages

As it's only 1K the simplest is a fast copy loop. \ (src)=>start of source data LDA #19:JSR OSBYTE :\ Wait for VSync LDX #4:LDY #0 LDA #&7C:STA dst+1:STY dst+0 .loop LDA (src),Y:STA (dst),Y INY:BNE loop:DEX:BNE loop RTS The copy loop needs a little more work I think. It copies the same page 4 times
by dp11
Tue Sep 24, 2019 8:40 pm
Forum: hardware
Topic: Open source A5000 RAM
Replies: 14
Views: 814

Re: Open source A5000 RAM

I'd also add a little decoupling for the buffers easy not to fit if it isn't required.
by dp11
Tue Sep 24, 2019 8:35 pm
Forum: hardware
Topic: Open source A5000 RAM
Replies: 14
Views: 814

Re: Open source A5000 RAM

might as well put all the smt on one side. Looks good.
by dp11
Thu Sep 19, 2019 6:42 pm
Forum: past events & exhibitions
Topic: Acorn World and ABUG meetup, Cambridge 20-22nd September 2019.
Replies: 249
Views: 10089

Re: Acorn World and ABUG meetup, Cambridge 20-22nd September 2019.

If anyone needs Pi stuff then there is a Raspberry shop in Cambridge.
by dp11
Sun Sep 08, 2019 9:40 am
Forum: off-topic
Topic: Odd Peripheral Goings-On With RPi4
Replies: 32
Views: 951

Re: Odd Peripheral Goings-On With RPi4

Okay, but to be clear throttling doesn't turn anything off all that happens is the clock rates are turned down, but not stopped until the temperature recovers.
by dp11
Sat Sep 07, 2019 10:22 pm
Forum: off-topic
Topic: Odd Peripheral Goings-On With RPi4
Replies: 32
Views: 951

Re: Odd Peripheral Goings-On With RPi4

Doesn't sound like a heat problem to me. Not sure heat was a surprise as early adopters reported they run hot and then start throttling back automagically an£ turning bits off, Can you provide any reference to "turning bits off"? You mean cpu throttling on the pi? I think Beebmaster has already dis...
by dp11
Sat Sep 07, 2019 8:33 pm
Forum: off-topic
Topic: Odd Peripheral Goings-On With RPi4
Replies: 32
Views: 951

Re: Odd Peripheral Goings-On With RPi4

unlikely to be the issue but there is new beta firmware for the VLI USB chip. might be worth a try...
by dp11
Sat Sep 07, 2019 6:51 pm
Forum: off-topic
Topic: Odd Peripheral Goings-On With RPi4
Replies: 32
Views: 951

Re: Odd Peripheral Goings-On With RPi4

Doesn't sound like a heat problem to me.
Elminster wrote:
Sat Sep 07, 2019 3:02 pm
Not sure heat was a surprise as early adopters reported they run hot and then start throttling back automagically an£ turning bits off,
Can you provide any reference to "turning bits off"?
by dp11
Tue Aug 27, 2019 9:08 am
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7348

Re: Raspberry Pi to 1MHz bus interface

Audio via the 1MHz bus is a bit noisy, but does make M5000 nice and easy to try. One of the bigger Pis with an audio jack gives stereo and better quality.

I'm sorry I will get around to sorting out the email/ PMs I have from people.
by dp11
Thu Aug 22, 2019 7:45 pm
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

Mesa issue will be fixed in 19.2. They're aiming to have a release ready by the 10th of September. So shortly afterwards there should be a Pi release.
by dp11
Sun Aug 18, 2019 9:38 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

Excellent thanks for letting me know.
by dp11
Sat Aug 17, 2019 5:22 pm
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

It's possible that fix was back ported into the drive raspberry pi released to fix libre office.
by dp11
Sat Aug 17, 2019 12:02 pm
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

The only reason I think the fix is in the latest driver is that libre office works. I will try and investigate.
by dp11
Sat Aug 17, 2019 9:31 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

I'm pretty sure that fix is in the latest driver.
by dp11
Sat Aug 17, 2019 9:13 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

I did miss that thread. Thanks for the pointer
by dp11
Sat Aug 17, 2019 9:02 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

If they are happy to help can they see if the pointer in libre office works. Ie just to confirm that they have the latest driver. I'll ask my friends at pi if they know of anything else.
by dp11
Fri Aug 16, 2019 11:10 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

I don't know about OR and AND, but I suspect they are also fixed. The driver certainly has had the XOR fix for a while now.
by dp11
Fri Aug 16, 2019 11:04 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Pizero will be fine. I don't have all the figure to hand , but PiZero(w) ( ARM1176JZF-S ARMv6 1GHz $5.00 to $10.00 +TAXes ) armcode 6502 : 290MHz RPi3B+ ( Cortex A53 ARMv8 1.4GHz $35.00 + TAXes ) RPi3A+ ( Cortex A53 ARMv8 1.4GHz $25.00 + TAXes ) should work but untested armcode 6502 : 339MHz lib6502...
by dp11
Fri Aug 16, 2019 10:33 am
Forum: emulators
Topic: Raspberry Pi 4
Replies: 22
Views: 1024

Re: Raspberry Pi 4

Sadly the Raspberry Pi 4, running Raspbian Buster, currently has a graphics driver bug (the glLogicOp function is broken) which affects BBC BASIC for SDL 2.0 ; specifically the OR, AND and XOR plotting modes (GCOL 1 to GCOL 4) don't work. This causes issues in the IDE and a number of the supplied e...
by dp11
Sun Aug 11, 2019 9:54 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

*FX 151,230,11 is PDP-11 on PiTubeDirect
by dp11
Sun Aug 11, 2019 9:10 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

As only one core is used and video output is not used., I've not seen the temp go above 55c.

PiTubeDirect turns of throttling.
by dp11
Sun Aug 11, 2019 8:19 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

I'm currently using my Pi4 Powered off my master, but the master doesn't have much load. Looking around the internet I see some people are over clocking the Pi4 to 2GHz others get a lees of a boost. Might be worth a try if you want even more performance.
by dp11
Sun Aug 11, 2019 12:55 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

I've had a few spare minutes and done a bit more work on the Pi4. On the dom_tmp_1 branch I've improved the the 6502 performance for the RPi4. RPi3B+ (1.4GHz) armcode 6502 : 339MHz lib6502 : 131.56MHz Z80 86.78MHz ARM 151.46MHz nativeARM : 20,735MHz RPi4 ( 1.5GHz) armcode 6502 : 370MHz lib6502 : 237...
by dp11
Mon Aug 05, 2019 4:17 am
Forum: hardware
Topic: Pi Tubedirect
Replies: 41
Views: 1747

Re: Pi Tubedirect

Try *ex.! Boot
by dp11
Sat Jul 06, 2019 2:54 pm
Forum: software: other
Topic: How does BeebAid turn off ROMs?
Replies: 8
Views: 431

Re: How does BeebAid turn off ROMs?

Just writing to the last 24bytes is unlikely to work. I suspect it fiddles with the ROM byte in zero page
by dp11
Fri Jul 05, 2019 9:54 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7348

Re: Raspberry Pi to 1MHz bus interface

The no fit resistor is part of a voltage divider that turned out not to be needed.

The pdf contains a 3d image that you can rotate so you need real acrobat.
by dp11
Mon Jun 24, 2019 6:05 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1159
Views: 123357

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

PiTubeDirect now supports the new Raspberry Pi4 (see :https://www.raspberrypi.org/products/raspberry-pi-4-model-b/) My work so far should be considered as beta. Cores programmed in C see a good performance increase . Arm native core is now so fast some work is needed on the CLOCKSP program as I get ...
by dp11
Fri May 31, 2019 6:37 pm
Forum: hardware
Topic: 1MHz bus and JIM interoperability
Replies: 65
Views: 2538

Re: 1MHz bus and JIM interoperability

I think IRQs when FCFE downwards is used may need some thought.
by dp11
Mon May 20, 2019 8:23 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7348

Re: Raspberry Pi to 1MHz bus interface

It is clear to me that I'm a bit slow at ordering and sending out hardware kits . Does anyone want to support / take over that hardware supply? I still want to support this and future projects. If someone could take the load off me I can focus on development work.