[sebhc] Emulator future? + request for tools

[Scott LaBombard]

Hi,

The 8251 is indeed tricky to initialize. Somewhere in my travels (perhaps
the spec sheet) I've found that delays between initialization commands are
often necessary. Here is my 8251A init routine that seems to work quite
reliably:

CONSTAT EQU     0FBH    ;IO STATUS PORT (H8-5)
CONDATA EQU     0FAH    ;IO DATA PORT (H8-5)
CONRST  EQU     040H    ;8251A UART RESET
CONMODE EQU     04EH    ;8251A MODE WORD (16x clk,8,N,1)
CONINIT EQU     035H    ;8251A COMMAND WORD SETUP

URTINI: MVI     C,003H          ;SEND 3 0's TO CLEAR UART (PER SPEC SHT)
URT1:   MVI     A,000H
         OUT     CONSTAT
         DCR     C
         JNZ     URT1
         MVI     A,CONRST        ;UART INTERNAL RESET COMMAND
         OUT     CONSTAT
         NOP                     ;DELAY
         MVI     A,CONMODE       ;SEND MODE COMMAND TO UART
         OUT     CONSTAT
         NOP                     ;DELAY
         MVI     A,CONINIT       ;INITIALIZE UART
         OUT     CONSTAT
         RET


Scott

----- Original Message ----- 
From: "Dwight K. Elvey" <dwight.elvey at amd.com>
To: <sebhc at sebhc.org>
Sent: Thursday, May 27, 2004 10:53 PM
Subject: RE: [sebhc] Emulator future? + request for tools


> Hi Jack
>  No, I have that with my Z80 H8 machine. I expect it'll
> work right away with the H8-4 since the ports are the same
> as on the H89 for the LP serial. The LP port on the H89
> connects with a straight serial cable. I expect the H8
> to do the same. If not, I do have a gender changer and
> jumper box.
>  I just have to look up my 8251 init code for the H8-5
> board. I can make another bootstrap for that quick enough.
> 8251's are tricky to get initialized.
> Dwight
> 
> 
> >From: "Jack Rubin" <jack.rubin at ameritech.net>
> >
> >> 
> >> Hi Jack
> >>  I have a tool that I've not released yet that I use. It 
> >> transfers an image between the H89/90 and a PC through the 
> >> serial ports. 
> >... 
> >> It can be used to transfer images to and from the 
> >> H8x machine, as well.  I'd like to check it out on at least 
> >> the H8-4 configuration before making the first release. I'll 
> >> then make another release for those that are restricted to 
> >> talking through only a H8-5 board.  Patience please. I didn't 
> >> intend to take as long as I have but it should be ready soon. Dwight
> >> 
> > 
> >I'm looking forward to it - do you need to borrow an 8-4 board for
> >testing?
> >
> >Jack
> >
> >--
> >Delivered by the SEBHC Mailing List
> >
> 
> 
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