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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

1389.0. "Parallel printer port specs?" by UKARC1::CHAMBERLIN (Ian Chamberlin) Tue Dec 07 1993 08:35

Hi,
	Can anyone provide me with the electrical specs for the parallel
printer port on the Atari ST(E). 

	I'm particularly interested in the output drive currents and
input load currents for the data lines. Also whether its a true tristate
bidirectional port or one of those quasi/bidirectional things with with
open-drain outputs and pseudo passive pullups. 

	Many thanks,
			Ian.
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1389.1Some info. on parallel port...FAILTE::ROBSONBMon Jan 10 1994 09:4636
    
    I have an info. file which doesn't, I'm afraid, give the detailed
    information you require, but FWIW here is what little information
    about the parallel Interface I have here:
    
    'ST parallel interface supports Centronics STROBE from the YM-2149
    PSG for data synchronization and Centronics BUSY to the MK68901 MFP
    (ACKNLG is not supported) for handshaking. Eight bits of read/write
    data are handled through I/O port B on the PSG at a typical transfer
    rate of 4000 bytes/second'
    
    Parallel Port Pin Assignments:
             ST						DB 25S
    PSG I/O A   1  ---	Centronics STROBE ------->
    PSG I/O B	2  <---	Data 0------------------->
    PSG I/O B	3  <--- Data 1------------------->
    PSG I/O B	4  <--- Data 2------------------->
    PSG I/O B   5  <--- Data 3------------------->
    PSG I/O B   6  <--- Data 4------------------->
    PSG I/O B   7  <--- Data 5------------------->
    PSG I/O B   8  <--- Data 6------------------->
    PSG I/O B   9  <--- Data 7------------------->
    MFP         11 <--- Centronics BUSY----------
            18-25  -----------Ground-------------
    
    Signal characteristics:
    
    pin 1	TTL levels, active low.
    pins 2-9    TTL levels.
    pin 11      TTL levels, active high, 1k pullup resistor to +5V dc.
    
    The data is believed accurate, hope this helps,
    
    Best Regards,
    Brian