Hi Garth,

I am putting this project of mine on hold an may start from scratch.
It looks like even a physical 65C816 board design would be more simple and require fewer parts. I will let you know what I come up with.

Greg

Hi Daryl,

Yes I have considered the back side. All caps and resistors (smd) are located on the back. I'm using standard routing techniques. There is really not enough room unless I start from scratch on the art work. Things are so tight now that my minumim land width and spacing is six mils which ...

Yes, it is for lack of room. The plan is to make the 65C02 and 65C816 interchangable. The problem is that the foot print of the cpld can't be any larger than that of the processors and 65C22s. Every available I/O pin of the cpld is occupied for the 65C02 glue logic. If I am to demultiplex any bank ...

Okay, I have a 65C02 SBC design which has been completed and proven in a real circuit board. Now I am redesigning it removing some things and adding some things. I feel that it should be made 65C816 compatible or maybe even strictly 65C816. The board is all surface mount. Size is 2.8 x 4.0 inches ...

>How about the programming hardware though?

They require an interface called a byte blaster or bit blaster. I got mine free but there is someone I think who posted a schematic on 6502.org that is identical to mine.

>You can still get 65c51's

Speed is the main reason That I don't use 65c51s. I've ...

Garth

First please except my apology for seeming like I was rejecting your experience and wisdom. The Word says that those who reject wisdom are in trouble.

>What kind of logic programmer do you have, and how do you like it?

I have been learning to use the Max+II software from Altera and have ...

Garth

I have run into problems in the past by not gating 02 with R/W to obtain OE and WE. The new W65C22s IRQ can't be wire ORed and non 65xx devices often require seperate read write lines (OE and WE again).

You are right of course about don't complicate things if not needed and from personal ...

Okay, can't argue with that at all. I have alway forced myself to keeping the I/O in zero page specifically 80-ff which complies with WDCs development stuff.
I may reconsider after seeing your logic. I will get back with you on it after I've had time to study it in detail.

I agree Garth

I'm just looking for ways to keep glue logic reduced to a minimum. For example, with an Altera CPLD and using the 65C02 the least pin count device can be used to take care of memory and have pinout room for up to eight 16 byte blocks for I/O but if address/data demultiplexing plus ...

Thanks for the reply.

I've gained a little more knowledge about the subject since the posting.
As you wrote, BRK and COP are identical except for the vector address.
What I didn't know was that the signature byte is loaded into the stack.

As for the 65C816 control lines, I was wondering for ...

Hello,

Could someone direct me to references on how to use the COP instruction and on how the VDA, VPA, VPB, and Abort lines are typically used?
There is an abundance of information on 65C816 programming but there seems to be very little on the hardware use.

John West,

The RS485 sounds like what I'm looking for. I will seriously investigate it.

Garth,
Thank you for the valuable information that you have provided.

Greg

Sorry for the late reply

What I ment by off board is long distance communications like across a factory floor. RS232 for instance except you can't directly connect multiple devices to an RS232. CAN means "Controller Area Network". You can connect multiple devices directly to the common CAN bus. It ...

Garth

I'll look at the bit banging deeper. I was orignally going to emulate a uart with the 65C22 using bit banging for a modem connection but decided simplisity is better when possible.
What do you think is good for multiple off board common serial connections? I have been looking at the CAN ...

Garth

Actually, it's been so long sense I have looked at Microwire, SPI and I2C that I have forgotten some of their spicifics. My main concern now though is data modems. I feel confortable that the 65C22 can directly adapt through driver routines with most of the serial standards. Now I know who to ...