Name      23211A1;

Assembly  0001;
Revision  1.0;
PartNo    E80 74S288;
Device    f1508ispplcc84;

Company   None;
Designer  Digital Equipment Corporation;
Location  None;
Date      March 2018;

property ATMEL { jtag=on };
PROPERTY ATMEL { preassign keep };
PROPERTY ATMEL { TMS_pullup=on };
PROPERTY ATMEL { TDI_pullup=on };
/* PROPERTY ATMEL { pin_keep OFF }; */
/* PROPERTY ATMEL { open_collector = INT_RQST }; */

/*
 * 23211A1 is a 74S288, programmed to drive latch enables during verious IOTs.
 * These enables are used by E69 and E79 to gate clocks to the right latches.
 * An 74S288 has 5 address inputs, an enable, and 8 data outputs.  In this 
 * case, the inputs indicate which IOT is executing.
 * The outputs are the various clock enables for various internal registers.
*/

/*
 * The 74S288 is a tri-state device, if G is inactive, the 
 * outputs are undriven.
*/
Pin 15 = !G;
/*
 * The IOTs/events which generate clock gating here:
*/
Pin 14 = !RTF;
Pin 13 = RTS_OR_RMF;
Pin 12 = !CDF;
Pin 11 = !CIF;
Pin 10 = !NEW_FIELD;
/*
 * The outputs get the clock to set the corresponding register:
*/
Pin 1 = set_int_inh;
Pin 2 = set_uf;
Pin 3 = set_ufb;
Pin 4 = set_db;
Pin 5 = set_df;
Pin 6 = set_if;
Pin 7 = set_ibb;
Pin 9 = set_ifb;

/*
 * Interrupt inhibit ia aet be RTF, RTS, RMF, or CIF.
*/
set_int_inh = RTF # RTS_OR_RMF # CIF;
/*
 * UF is set by NEW_FIELD.
*/
set_uf = NEW_FIELD;
/*
 * UFB is set by RTF, RTS, or RMF.
*/
set_ufb = RTF # RTS_OR_RMF;
/*
 * DB is set by RTS, RMF, or CDF.
*/
set_db = RTS_OR_RMF # CDF;
/*
 * DF is set by RTF, RTS, RMF, or CDF.
*/
set_df = RTF # RTS_OR_RMF # CDF;
/*
 * IF is set by NEW_FIELD.
*/
set_if = NEW_FIELD;
/*
 * IBB is set by RTS, RMF, or CIF.
*/
set_ibb = RTS_OR_RMF # CIF;
/*
 * IFB is set by RTF, RTS, RMF, or CIF.
*/
set_ifb = RTF # RTS_OR_RMF # CIF;

/*
 * Here is where G is implemented, though it is tied to 
 * ground in practice.
*/
set_int_inh.oe = G;
set_uf.oe = G;
set_ufb.oe = G;
set_db.oe = G;
set_df.oe = G;
set_if.oe = G;
set_ibb.oe = G;
set_ifb.oe = G;