![]() A lot of the older 68000 adapters were byteswapped for some reason (eg on the Amiga)Įtchedpixels wrote on Mon, 03 September 2018 08:58 I can byte swap in software. I'd rather do that than have a world where we have a mix of swapped and not swapped boards, that way lies madness. Plasmo wrote on Sun, 02 September 2018 14:43 Alan, I will dig out the two files that were combined to make n and attach them later. Powering Z280RC with USB-serial adapter only works for me intermittently, I don't trust it. The USB-to-serial adapter may not be able to source that much current or not able to keep 5V in good regulation even if it can source the current. This is because while the nominal current of Z280RC is 300-350mA, but peak current when read/write CF disk may be higher. It is important to add 1 ms delay to every line and enable transmission of binary data to send "n".īefore you try that, I like you to power Z280RC with a separate 5V power supply (be sure to remove the 5V jumper, T3). So we need to rewrite the boot sector in UART bootstrap mode: When the CF activity light stays on, it most likely means the CPLD state machine is able to set up the boot sector of CF in read mode but Z280 can't execute the code correctly, possibly because the bootstrap code is corrupted. Z280 executes the data stream coming out of the CF data FIFO (a tricky piece of code) and completes the bootstrapping process and clean up the mess created by the hardware state machine, if all goes correctly. It waits for the CF data to be ready (that's when CF activity light turns on), remaps the CF read register to 0x0 and releases Z280 reset. When power up or manual reset, the hardware state machine in CPLD keeps Z280 in reset while issuing a CF read command to boot sector of the CF. The CF activity light (the blue or red LED on the small CF adapter board) should not stay on very long. So that's all you need to connect when using a different USB-to-serial adapter. The serial port only needs ground, Transmit and Receive. When initially powered on (or pressing the reset button), you should see a brief flash of CF activity LED indicating CF is bootstrapping (this is assuming bootstrap jumper, T5, is inserted). There is a voltage supervisor on-board that'll force a reset when voltage is below 4.6V. Make sure your voltage is between 4.8V to 5.3V. How was the Z280RC powered when CP2102 died? Did you have a separate power supply via the 2.1mm x 5.5mm power plug? If you can measure the current, the nominal current when running at standalone mode is 300mA-350mA. However, the immediate problem is your Z280RC not working starting with a non functioning CP2102. It appears, however, you are moving CF disk between PC (sorry, I believe you are a Linux guy), and Z280? If so, I need to think more about the byte swap issue. It is all very confusing, but as long as you don't transfer data between PC and Z280RC by physically moving the CF disk between the two machines, the byte-swap-ness is not a problem. It took me a long while to realize that Z280's D8-D15 is the least significant byte of a word access while D0-D7 is the most significant byte. ![]() When I designed the hardware I naively connected Z280's D0-D7 to CF interface's D0-D7 and Z280's D8-D15 to CF interface's D8-D15. I finally realized that a couple months ago when trying to make sense out of CF manufacturer ID. ![]() Yes, the upper byte & lower byte of CF interface are swapped.
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