Denial

Yes. All STM32 has a memory management unit / controller. All can handle Flash memory, Static RAN as well as QSPI SD cards. Some, as with the STM32F722, can also handle dynamic memories natively and automatically. From the MCUs and the programs perspective these 8Mbyte of memory is one long linear m...

Mr Senior Cartridge has come a bit forward. It's main component is a 32bit MCU STM32F722 from ST and a 64Mbit DRAM from Windbond. The MCU simply emulates the Flash and RAM in software. This gives every possibility to do some fancy stuff besides the obvious and standard features of a ram expansion. T...

Hi, No. Not Junior. It is by design quite limited. It should be seen as a low cost RAM expansion with the possibility to have 15-63 custom cartridges. I do this mostly to test the programmable logic. This is a series of components I right now are going to use professionally, so junior was a very goo...

Thanks for your comment Jim and yes, that is true. However to the best of my knowledge the 29F040b is an obsolete part, although 29F040C is active. This is originally aimed for 128k FLASH and the 39SF010 is the cheapest one I could find in TSOP-32. At least from the ordinary distributors. I try to a...

Is the flash memory writable by VIC 20 (and how)? because I read from the datasheet that it need particular HW procedures.... Yes it is. The FLASH needs a "Magic Sequence" to unlock the different commands. Chip erase, sector erase (4k), ID readout, and programing. You write (for these FLA...

And to answer the question ... Why the funky PCB shape? Well, with this shape I can get most out of the PCB production panel. The area is reduced to 68% per pair. This should yield 23 customer panels (with 2 product PCB each) on each production panel. This also speeds up (= lower placement cost) the...

Thanks!

I will do my utmost to keep the cost down. A challenge I enjoy, and which are part of my daily job.

Thanks!

A new version of the hardware has been sent to production. Only a few smaller changes ... - Replaced the octal latch with a edge triggered variant to save one delay line in the GreenPAK. - Added an external single gate inverter for RD generation to the flash memory. - Added the possibility for a lar...

Another weekend with some time for junior. Soon time to start on the real cartridge. Anyway. The logic fabric is finished, but there is one minor thing to fix. All the bank switching, long/short reset, write protect, etc works very well. The firmware for setting up the configurations also comes alon...

All banks including RAM1-3 and IO RAM tested and works.

Next will be to test the config and bank latch, run some extended memory testing, and start working on the real logic.

BoM including PCB is still under 5 USD for this simple expansion.

That is probably it for the weekend.

Quick test with only BLK1 connected to the RAM through the logic and it seams also to work.

Set up the environment for developing the hardware description for the small programmable logic. At least nothing is blocking the bus for the VIC-20 and it starts, so I guess the smoke test is passed. The reset switch also works, although that would have been pretty embarrassing if you failed on. Th...

Thanks again Jim.

... and soldered. Everything except the digital FPGA. That will be connected to the emulator to start with.