AN00005.TXT

Advanced Communication Board Developer's Toolkit 1995
    

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Subject: Master / Slave Clock Application Note.

SITUATION:
Attempting to simulate a DCE device communication in Synchronous Mode
with a DTE device, using two ACB cards. It will be necessary for one ACB to 
provide clocks (DCE) and the other to receive clocks (DTE).

SOLUTION:
The solution to this problem relies on three factors, the values written to
the 85x30 registers, the jumper options set on the ACB adapter, and the cable
connections between two devices. For this example, assume two ACB cards are 
being used.

In the application program, the two 85x30 registers that are important to
this example are Write Register 11 and 14. On the Master (DCE) node, WR14
should have bits D0 and D1 set (03 hex). WR11 should be programmed with a
56 hex (see below). The Slave (DTE) node should program WR14 with bits D0 and
D1 reset (00 hex) and WR11 to 00 hex (see below).

Write Register 11 values:

	  MASTER (56h) >> REC CLK	=  BR GEN
			  TRANS CLK	=  BR GEN
			  /TRxC 	=  OUTPUT
			 /TRxC OUT	=  BR GEN

	  SLAVE  (00h) >> REC CLK	= /RTxC PIN
			  TRANS CLK	= /RTxC PIN
			  /TRxC 	= INPUT
			  bits D1 and D0 are XX (Don't Care)

The jumper setting for the ACB-II, ACB-III, ACB-IV and ACB-V are listed below.

     ACB-II JUMPER SETTINGS:  (| = PLACE JUMPER, 0 = JUMPER OFF)
          MASTER:
            E4  00|00  

          SLAVE:
            E4  |000|

     ACB-III JUMPER SETTINGS: 
          MASTER:
            E3, E6  |0000|      E2, E10  |000|

          SLAVE:
            E3.36  0|000|      E2, E10  |0|0

     ACB-IV JUMPER SETTINGS:
          MASTER:
            E1, E2  00||0||00

          SLAVE:
            E1, E2  0|0|00000

     ACB-V JUMPER SETTINGS: Cannot source clocks without modification.
          MASTER:
	    MUST HAVE MODIFICATION, PLEASE CONTACT TECHNICAL SUPPORT.

          SLAVE:
            N/A