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[[Rodrik Studio]] announced its PicoCPC expansion card, which is created with the help of [[FreddyV]] (the author of the [https://github.com/FreddyVRetro/ISA-PicoMEM PicoMEM ISA card for IBM PC]).
[[File:PicoCPC proto2proto.jpegjpg|600px]] [[File:Modular PicoCPC.jpg|600px]]
<br> == Architecture == The PicoCPC use a Pico2, connected via multiplexor. This let enough pin to add an I2S DAC, MicroSD and some more control signals. The Final PicoCPC board will be really different, with soldered RP2350BDirectly soldered. No 5V pin go to the pico. We use some 1 buffer, 1 level shifter, 3 multiplexers. We write to the CPC with 3.3V, we use 5V to the CPC only to drive some signal like A15 for C3 memory mode and IOReq to disable intern floppy. We prefer to have somerthing between the Pico and the CPC, as even if 5V work now, there is no guarantee that the boards will work after some years of intensive usage.It is really better to be carefull.
The board can decode any I/O port and of course RAM/ROM cycles. As it use a Pico2, its RAM is doubled vs Pico1 and it can access a 8MB PSRAM as well.
The PicoCPC does NOT use a CH376 chip, everything is done with the Pico itself. PicoCPC handles FAT12, 16, 32, ExtFS. CH376 will be emulatedon the board, with nothing to do at the CPC side.
There is no external ROM, so the microntroller access the emulated RAM/ROM and USB/MicroSD at the same time: Direct write from the uSD to the CPC emulated RAM at 3MB/s (For example).
The PicoCPC is clocked at 366Mhz. So it is not as powerful as the [[RSF3]] clocked at 480Mhz. But it is more powerful than the [[M4 Board]] clocked at 168Mhz. [https://www.spinpoint.org/2015/10/23/cortex-m4-board/ Source]
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=== Multiplexers ===
The "Secret" of the PicoMEM/PicoCPC is its multiplexers. [https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/picocpc/msg249997/#msg249997 Source]
It allow to limint the number of I/O needed and act as a Voltage converter at the same time.
The Pi Pico allow to have multiple PIO core, plus the main core working together in parallel,so the PIO manage the Multiplexer, reconstruct the Address, while CPU core detect and manage the Control signals, Read in advance the High part of the address to jupt to the correct code.
(IO MEM Read or Write, Bank number)
So, when the Main core is in the correct code section, it can read directly the full Address from the PIO.
The PicoCPC use only 12 I/O to manage all the address, Data and Control signals. We can add 2 pin only to control the multiplexer.
Then, the CPC bus is "manipulated" Via ROMDIS, RAMDIS, RD, A15, IOREQ (Pico Output)
With this way to do, it is possible to be almost as fast with multiplexing that without.
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* Reset button
C3 mode to arrive in the next hardware release (update 09/04/2025: C3 mode works perfectly fine). And much more for the final hardware release: vocal synthesizer, cpr cartridges, usbmouse, wifi, nfc, ... The Pimoroni hardware is also being evaluated. [[File:Pimoroni Picocpc.jpg|600px]]
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*"The HDD part isn’t great; binaries that load other binaries won’t work. In the end, I could only put a few games on it."
On 12/04/2025, Rodrik posted on CPCwiki forum:
I wanted to clarify few things, there is no interest list, nowhere to register to. When the card is ready enough, it will be made available via resellers in France, UK and maybe US.
I still don't know when this will happen, the card did progress of lot since the start in December last year, this means 4 months ago. But I think 3 more months at least are required to make it work properly on all CPC flavors.
The card is currently limited by the RB2350, I do not have enough gpio, so I either use an oled screen, either I2S DAC, either use the pins to drive some signals on the bus. So it requires a new revision with e 2350B soldered on board.
Feature list is unknown yet, but it will grow over time. The card will be available with lot of hardware, but only future firmware revision may make use of it.
On 04/05/2025, Rodrik posted on its facebook page: https://www.facebook.com/100050156822393/posts/1220749709606912/
It's been a while since I posted here, so I'm here to give you some news about the future of PicoCPC.
4 days of work to get it routed after quite a few hours getting everything set up.
* USB-A port for a USB key initially on the HDD or for loading floppy disk images, cartridges, or ROMs, and more from the SD cards.
* USB-C port for flashing the PicoCPC.
* Micro DVI port, future if I can get there 😉
* Integrated DAC, we'll see what I can get out of it.
* Buttons for controlling floppy disk images without the CPC.
* 1MB of SRAM, for large cartridges or lots of memory/ROM.
* 16MB of flash, not usable by the CPC, too slow, but I could store things on it as ROM.
Daughter board
* Audio output
* Buttons
* NFC
The white square on the daughter board is the location of the OLED display.
This version, which could be v1.0, will be manufactured in late May.
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