mad@cpoint.clearpoint.com (Mike A. Davis) (03/21/91)
Hello netlanders,
I am dealing with writing a background debugger using the 68302, a 68000
family chip which is fairly new (very much so to me :). The 68302 has on-
chip serial communications, and it is the UART communications to the terminal
and keyboard which is giving me trouble. I am using a WYSE WY-85 terminal.
I am hoping someone might be able to answer a question or two:
1) I have the transmitter working just fine, but I want to handle the
keyboard input by having the receive buffers generate interrupts when
an input buffer is full. As far as I can tell, here is what needs to
be done (i.e. what I have done so far, but doesn't work):
- use serial channel 1 (SCC1 in documentation)
- set up baud rates to be same on UART and terminal (9600)
- set partity,etc, to be the same (7 data, 1 stop, no parity)
- set max receive buffer length = 1 (process each character)
- use all 8 receive buffers, enabling interrupt when buffer full
- I'm not using any control characters.
later, when I actually enable the receiver and interrupts:
- Enable receive buffer interrupt in the SCC Mask register
- Enable SCC1 interrupts in Interrupt Mask Register
- Set the V7-V5 bits in the Global Interrupt Mode register to 100
binary. This should vectory SCC1 interrupts to Vector 77 (decimal)
The keyboard handler interrupt is installed at vector 77, but never seems
to be invoked.
Any ideas? Working code would be appreciated.
2) Anyone know of any good books on the 68302 or serial communications via
UART? Either Motorola or third party books are OK. Right now all I
have is the Motorola 68302 User's Manual.
3) Does anyone know of any 68302 emulators, either hardware or software, that
might make it easier to debug and/or get a faster turnaround? Right now
I am burning the code into EPROM's and using a logic analyzer to trace
execution.
Thanks in advance for any help. My incoming email is kind of flakey, but
you can try mad@[wolfy. or cpoint. or <nothing>]clearpoint.com. I am willing
and able to ftp large code should anyone choose to make it available. Net
responses, of course, are welcome.
Thanks,
Mike Davis