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How to get output from SIO with Intel 8251A USART

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  • IBM_User
    replied
    On my first SIO-2 it was a bad 8216 (bi-directional bus driver), and the second SIO-2 did not have any problems,
    it was the DIP switch for the parity setting at the Hazeltine who did not make contact.
    After moving it several times this problem was also solved.

    Leave a comment:


  • Nama
    replied
    what was the fix?

    Leave a comment:


  • IBM_User
    replied
    Problem seems to be solved, thanks you all!

    Leave a comment:


  • IBM_User
    replied
    Both sides 8 data bits, no parity and 1 stop bit.

    Leave a comment:


  • Chuck(G)
    replied
    I assume that you've set the terminal to 8N1 and the 8251 likewise. For now, forget parity.

    Leave a comment:


  • IBM_User
    replied
    Currently I read the manual from the terminal in which stands:

    If a character is received with a parity error when EVEN or ODD parity is selected,
    the character will be replaced on the display with a ? symbol

    Leave a comment:


  • IBM_User
    replied
    I changed full duplex to half duplex on the Hazeltine, now I get various characters, but not as expected.

    Only 43H to get an "C" seems to work?!

    Leave a comment:


  • IBM_User
    replied
    I'm gonna sick!

    I attach two photos of what I get.

    I checked the code twice, memory board is working, perhaps a terminal setting?
    At the Hazeltine I can only setup baud rate and parity via dip switches, so I think that's not the problem.

    Frank, on which system did you use the 8251A?

    IMG_2669.jpg

    IMG_2670.jpg

    Leave a comment:


  • Frank S
    replied
    Hello Matt,
    i just try the code on a real 8251.
    It works like a charm.
    Frank

    Leave a comment:


  • IBM_User
    replied
    Yes, on both boards works the ECHO routine.

    Now I gonna check the SENSE routine on the another board.

    Leave a comment:


  • Frank S
    replied
    Originally posted by IBM_User View Post
    Anyway, the ECHO routine works flawless, any key which I press on the console (Hazeltine 1410) gets displayed on the screen.
    And this with both SIOs you have?

    Frank
    @smp: No, you are not hallucinating. I correct the code above.

    Leave a comment:


  • IBM_User
    replied
    I'm sorry, I was a bit hurry.

    Anyway, the ECHO routine works flawless, any key which I press on the console (Hazeltine 1410) gets displayed on the screen.

    With the SENSE routine, I get a continous stream of question marks without hitting any switch on the frontpanel.
    When I hit an switch (switches A8 through A15) the stream stops or changes to an "@" sign.

    I can't generate any other character than these.

    @smp: I changed that several hours before, without luck.

    Leave a comment:


  • smp
    replied
    Originally posted by Frank S View Post
    Chuck,thats right.
    I corrected the code for checking the BIT 0 of the 8251 Status register for beeing empty.

    SENSE-Switch SIO Out Routine
    Code:
    0001 0000 	CDAT 	.EQU 	02H 	;8251 DATA PORT
    0002 0000 	CCOM 	.EQU 	03H 	;8251 COMMAND PORT.
    0003 0000 	SENSE 	.EQU 	0FFH
    0004 0000 3E 00 	MVI 	A,00H 	;INITIALIZE UART.
    0005 0002 D3 03 	OUT 	CCOM
    0006 0004 D3 03 	OUT 	CCOM
    0007 0006 D3 03 	OUT 	CCOM
    0008 0008 3E 40 	MVI 	A,40H 	;reset command
    0009 000A D3 03 	OUT 	CCOM
    0010 000C 3E 4E 	MVI 	A,04EH 	;Mode register 8,1,n 
    0011 000E D3 03 	OUT 	CCOM
    0012 0010 3E 37 	MVI 	A,37H 	;Command register
    0013 0012 D3 03 	OUT 	CCOM
    0014 0014 DB FF 	LOOP: 	IN 	SENSE  <--------------- *** shouldn't this be CCOM? ***
    0015 0016 E6 01 	ANI 	01H
    0016 0018 CA 14 00 	JZ 	LOOP
    0017 001B DB FF 	IN 	SENSE
    0018 001D D3 02 	OUT 	CDAT
    0019 001F C3 14 00 	JMP 	LOOP
    0020 0022
    0021 0022 		.END
    Frank
    It seems to me that the input instruction at the LOOP: label should be IN CCOM, not IN SENSE, or am I hallucinating?

    smp

    Leave a comment:


  • Frank S
    replied
    Hello Matt,
    please explain a little bit more detailed, what is working and what do you get for results.
    I make an mistake yesterday evening in the code.
    Try the code below.
    Frank

    Code:
    0001   0000             CDAT	.EQU	02H		;8251 DATA PORT
    0002   0000             CCOM	.EQU    03H             ;8251 COMMAND PORT.
    0003   0000             SENSE	.EQU	0FFH
    0004   0000 3E 00       	MVI  	A,00H		;INITIALIZE UART.
    0005   0002 D3 03       	OUT  	CCOM
    0006   0004 D3 03       	OUT  	CCOM
    0007   0006 D3 03       	OUT  	CCOM
    0008   0008 3E 40       	MVI  	A,40H		;reset command
    0009   000A D3 03       	OUT  	CCOM
    0010   000C 3E 4E       	MVI  	A,04EH		;Mode register 8,1,n
    0011   000E D3 03       	OUT  	CCOM
    0012   0010 3E 37               MVI  	A,37H		;Command register
    0013   0012 D3 03       	OUT  	CCOM
    0014   0014 DB FF       LOOP:	IN	SENSE
    0015   0016 D3 02       	OUT	CDAT
    0016   0018 DB 03       LOOP1:	IN 	CCOM
    0017   001A E6 01       	ANI	01H
    0018   001C CA 18 00    	JZ	LOOP1
    0019   001F C3 14 00    	JMP	LOOP	
    0020   0022             	
    0021   0022             	.END
    Last edited by Frank S; March 18, 2014, 06:23 AM.

    Leave a comment:


  • IBM_User
    replied
    Still no succes, only the ECHO routine will work.

    With my previous routine, not Franks one, I get a stream of question marks.
    I don't know why, because the SENSE switches were all in the down postion??

    Leave a comment:

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