Matthew Cook
2015-04-21 15:18:17 UTC
So I have been working for a while now off and on to learn some Z80 design
from an electronics and software standpoint. I think I posted here before,
but I was a bit too in over my head, and most of the work I had
accomplished failed ass I was taking on too much at once without enough
knowledge and testing... =(
Since then, I have done a bunch of tests so far which can be seen here on
my blog, https://z80project.wordpress.com/ . Where I am currently at is
trying to print some strings out of the UART and also trying to implement
interrupts. During my last test the circuit which can be seen in the
attached PDF worked flawlessly with a small assembly test which was to echo
the key typed in the terminal emulator back and forth from the UART. This
test was set up to make sure that I had the stack correctly initialized,
and that CALL and RET were functioning properly. The current test that I am
working on is a routine to print out a string. the code can be seen in the
attached file. The problem is that it just does not work. I am not sure
where I went wrong. It seems very straight forward. Could it be that I just
got lucky during my previous test (same hardware as in the current
schematic) to have everything working in an echo program? I feel like it
should be easier to print a string than to echo keys back and forth on the
UART, but I guess not.
Any way thanks for the help ahead of time. I don't know very much so far
since I have not gotten very far into the expanding the design to figure
out more advanced concepts. I am eventually going to try and write a
monitor program and bring my design to a PCB, but before then I want
everything to work well on the breadboard, and know enough about Z80 design
before moving it off.
from an electronics and software standpoint. I think I posted here before,
but I was a bit too in over my head, and most of the work I had
accomplished failed ass I was taking on too much at once without enough
knowledge and testing... =(
Since then, I have done a bunch of tests so far which can be seen here on
my blog, https://z80project.wordpress.com/ . Where I am currently at is
trying to print some strings out of the UART and also trying to implement
interrupts. During my last test the circuit which can be seen in the
attached PDF worked flawlessly with a small assembly test which was to echo
the key typed in the terminal emulator back and forth from the UART. This
test was set up to make sure that I had the stack correctly initialized,
and that CALL and RET were functioning properly. The current test that I am
working on is a routine to print out a string. the code can be seen in the
attached file. The problem is that it just does not work. I am not sure
where I went wrong. It seems very straight forward. Could it be that I just
got lucky during my previous test (same hardware as in the current
schematic) to have everything working in an echo program? I feel like it
should be easier to print a string than to echo keys back and forth on the
UART, but I guess not.
Any way thanks for the help ahead of time. I don't know very much so far
since I have not gotten very far into the expanding the design to figure
out more advanced concepts. I am eventually going to try and write a
monitor program and bring my design to a PCB, but before then I want
everything to work well on the breadboard, and know enough about Z80 design
before moving it off.
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