Commander X16

Always check the datasheet on these things before making assumptions about how performant memory is. The APS6408L is a *synchronous* pseudo SRAM with a highly multiplexed ADQ bus and a tRC latency of 60ns. Strictly speaking, there is no way to meet the datasheet minimums at anything faster than 8MHz...

The biggest problem with SDRAM (or DRAM) is that memory access latency is relatively long and that latency has not changed much in the past couple of decades. E.g. an SDRAM with CAS latency of 2 typically has a tRC of 9-10 cycles. At 200MHz, that's 45-50 ns between random memory accesses. Their sequ...

I hope that I get this right, I'm interpreting the Verilog code for VERA: 1. Reset the accumulator (read from $9F29, DCSEL=6; or write bit 7 of $9F2C, DSCEL=2) 2. Perform first multiply 3. Add that product to the accumulator (read from $9F2A, DCSEL=6; or write bit 6 of $9F2C, DCSEL=2) 4. Perform you...

As I recall the DMA on NES lived in the 2A03 CPU.

It would be possible to have hardware external to VERA do DMA writes. The current VERA firmware could not keep up with writes every cycle so a delay would be necessary.

Wouldn't the internet be a more ideal software distribution medium? Modern flash storage is pretty stable; data loss is fairly unusual in my experience. I cannot think of a time when I lost data on one due to charge degradation. CDs and DVDs have well known sources of data loss: https://en.wikipedia...

It seems like you could get another 1 or 2 bits using the YM2151 timers.

Also, start with the first time setup guide: https://codeberg.org/smrobtzz/x16-esp-f ... 20Setup.md

Is there any documentation available for this board? I am particularly interested in the WebDAV support. Check the documentation on Git repo for the firmware: https://codeberg.org/smrobtzz/x16-esp-fw/src/branch/main/doc I pretty much live by the WebDAV functionality these days. Unfortunately Window...

That case was made for my OtterX. I still have a couple available up on Tindie (https://www.tindie.com/products/wavicle/otterx-8-bit-retro-computer/). Folks have also been using that Kickstarter C64 case with OtterX and Calypso for USB keyboard support. I'm not certain that I'm going to continue the...

This is a circuit I posted on Discord a couple of years ago. You can use it directly for two rows of 8 lights, or you can replace the 7402 with a 74138 and get 8 rows of 8 lights. It's kinda expensive for what it does because it requires a 74273 latch for each group of 8 lights, but it has been used...