Hi all
I've mailed Grant but I thought I'd ask here too.
Today I attempted to build a Multicomp (http://searle.hostei.com/grant/Multicomp/index.html?mmskip=1) after waiting weeks for the parts to arrive from China.
I wired the board with a single serial port, external SRAM and an SD card.
I installed the Altera Quartus software (what a palaver!), loaded the USB Blaster driver and opened the "Microcomputer.vdl" file. I configured it as a Z80 machine with full external SRAM, single serial port and SD card (basically, per the hardware setup). I finally got the thing to program the board but nothing happened. The programmer is set for the correct board. I noticed that each time I power cycled the board the three LEDs next to the JTAG header flashed at about once a second. Reprogramming the board seems to make the flashing stop. Does this mean that the board really isn't being programmed properly?
Anyway, suspecting a problem with the physical wiring, I went back into the VHDL and reconfigured, this time for a serial port and 4k internal RAM. In this mode, only the serial port is connected and active, so any wiring errors should be irrelevant. Naturally I checked the serial wiring again. Ran the programmer but nothing on the serial port at all. Swapped RXD / TXD but again nothing.
Trying with a different rs232 converter board which has LEDs on it, I noticed TXD was constantly on, and occasionally the PC reports that it cannot connect to the port. Something is definitely wrong.
The last thing I have tried us to lower all the clock speeds. CPU at 1mhz, serial at 9600 baud, still nothing.
I'm concerned though, because the setup seems to have a CTS line (no RTS) but my serial - TTL board only has TXD RXD GND PWR. No hardware handshaking at all. Maybe the port is waiting for CTS? I have tried connecting it to Vcc (asserts CTS all the time) and GND (because it is really !CTS) but neither work.
So I'm a bit stuck now and hoping for advice. My money is on the "programming the board" bit as the Altus software is complex and I am new to it. Tomorrow I will disconnect the SD card and SRAM, cut it back to the basics, but I'm pretty sure it won't make any difference.
Is there a way to test it?
Cheers
JonB
