Amiga ARM accelerator

dizzy · 294

dizzy

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on: June 24, 2019, 12:15:34 PM
Someone has made an attempt using STM32 mcu on an Amiga :)

https://youtu.be/tCeCAasLe3g

I remember brain farting with the idea on the old forum.

Had to try and use SDRAM and SRAM with wait signaling on my STM32F7 devboard and it seems to work. Can't hold the SRAM back for a long time or else the gfx dma glitches... :)

I would love to see the details from that project. The STM32 could be clocked from the 7MHz if divided by two first and then the clock output MCO could also drive the e-clock, it also needs to be divided by 2 first before being fed into the system. EDIT: Minimum input clock for hse is 4MHz so feed the 7M directly to it (via a level shifter) and the divide the MCO1 output fed by HSE by 2...

I had some other use for this 32-bit SDRAM interface board for STM32H7 that I've designed, but maybe I'll just stick it in my Amiga

https://youtu.be/4DWd3BKkug0
« Last Edit: June 24, 2019, 03:14:43 PM by dizzy »



salvatore

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Reply #1 on: June 24, 2019, 02:15:24 PM
good job :)



dizzy

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Reply #2 on: June 24, 2019, 03:03:59 PM
I have nothing to do with this, but looking at the pcb there is one familiar name on it...

https://www.ppa.pl/forum/elektronika/40065/amiga-i-arm-czyli-amiga-arm-accelerator-development-board

There are a lot of 5v tolerant GPIO pins on STM mcu's, they could directly be used to get the bus while the original cpu is still in it's socket (expansion slot), one of the STM32 timers could count the cycles if the original m68k would be wanted to run at first and set the rom at it's location.

Couple of signal mosfets driving the m68k reset line low until the MCU is up and running and when it is then let the mosfet(s) release the line. OS-rom could be put on a faster bus (QSPI Flash, megabytes of room ) and maybe just only copied to it from the motherboard.

Quad spi flashes can be memory mapped on stm32, only writes need more time. MCU can also execute code directly from the qspi.

Edit: bought some ic's but in the meantime I made a m68k in vhdl... Well not really, only a tiny portion of it, the free running e-clock

https://youtu.be/0wgtKx8PWt8

Hit also the first timing limit, Spartan-6 can only clock that logic at some 450MHz

Now the input clock is 50MHz and the e-clock 5MHz
« Last Edit: June 24, 2019, 10:52:44 PM by dizzy »



salvatore

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Reply #3 on: June 25, 2019, 12:47:26 AM
I don't use amiga classic anymore but these are good projects, still many use the old systems

hi