Bytesaver ii questions.

[Hugo Holden]

The ByteSaver uses PRDY to force a wait when a memory write cycle occurs to the board during a programming operation. In this case, the Sol does not generate its own wait state (since the ByteSaver is not in the range C000-CFFF), so you should be able to use the ByteSaver on PRDY without issue.

Mike

That is handy. I will try it. At least I know how to check it if it malfunctions. When it is working there should be zero cpu activity when the prdy is asserted by the Bytesaver, and its easy to see that by looking at the address lines with the scope at the same time.

[Hugo Holden]

So I assume the Matrox board must use PRDY because it has to stall reads/writes around video refresh access?

Mike

As I recall the data bit (just 0 or 1) from the the Matrox's ALT-512 RAM array is extracted by setting the RAM address for the pixel location and it is loaded to a latch. The PRDY output from the Matrox stalls the cpu until the data bit is steady at the output of this latch, before you read it from the port. Interestingly the previous card, the ALT-256 had no way to extract the data from the RAM. I made a program to extract the ALT-512 data to general RAM, so I could save an image, say drawn by a Light Pen, which is drawn directly into the Matrox RAM, not general RAM first.

I have attached the program that I wrote to do it, its called IMSTOR. It is not an efficient program, filled with many calls and the like, but I wast just learning how to do it.The program converts the Matrox's RAM bits into bytes for the general RAM memory file. The reverse program I wrote is called PLOT, which gets the bytes from general RAM and plots them as bits into the Matrox's RAM.

[Hugo Holden]

Look at the help menu. You’ll have to set the ByteSaver type with the BS command, the memory bank (0) with the BB command, and the address of the socket you’re using for programming with the PA command.

Mike

Mike,

Rather than just using the .com program, I sent the the .asm to the SOL, it took a while with PCGET as its a 64k file. Then I assembled and loaded it without problems which was very nice.

Can you tell me, when I use the "?" for the help menu, of course it is too long to fit on one screen and scrolls to the end. How can I scroll in a step by step manner to see the beginning, or interrupt the scroll. Is there a command or a / or something added like a keypress on the SOL that will do it ?

[deramp5113]

Can you tell me, when I use the "?" for the help menu, of course it is too long to fit on one screen and scrolls to the end. How can I scroll in a step by step manner to see the beginning, or interrupt the scroll. Is there a command or a / or something added like a keypress on the SOL that will do it ?

In CP/M, ctrl-s should pause and resume the output. There’s also an option in the program for a 16x64 character screen. Type “SS 0” and I think it will display help in 16 line pages for you.

Mike

[Hugo Holden]

In CP/M, ctrl-s should pause and resume the output. There’s also an option in the program for a 16x64 character screen. Type “SS 0” and I think it will display help in 16 line pages for you.

Mike

Thanks !

[Hugo Holden]

Mike,

With the CP/M program, I'm not sure of the implications of the programmer address. The program appears to be org'd at 100h and it appears to end around 13A3h, and you set the ROM address where the bytesaver is. Is the programmer address a section of memory set aside for the program to use during its execution ?

As an example, in my system running CP/M with 48k memory, if I have the bytesaver say starting at 6000h, where would be a suitable place to set the programmer address ?

[deramp5113]

From what I recall, the programmer address is the address of the socket you’re going to use to program. For example, if you enabled programming for the highest addressed socket, then set the programmer address to 7C00h for a ByteSaver at 6000h.

Mike

[m_thompson]

The programmer address is the address of the socket you’re going to use to program. For example, if you enabled programming for the highest addressed socket, then set the programmer address to 7C00h for a ByteSaver at 6000h.

This is correct. I just used this a few weeks ago.