Kawasaki 80C152, 80C51 technical specifications Kawasaki LSI USA, Inc Ver .9 KS152JB2

Models: 80C51 KS152JB 80C152

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KS152JB Universal Communications Controller Technical Specifications

mode_logic (n)

if (DCONn indicates burst_mode) return 1:

else if (DCONn indicates external_demand_mode)

{

if (demand_flag = 1) return 1: else return 0;

}

else if (DCONn indicates SP_demand_mode)

{

if {SARn = SBUF .AND. RI = 1) return 1;

else

if (DARn = SBUF .AND. TI = 1) return 1;

else

if (SARn = RFIFO .AND. RFNE = 1) return 1;

else

if (DARn = TFIFO .AND. TFNE = 1 .AND.

 

previous_cycle = instruction _cycle) return 1;

else return 0;

}

else if (DCONn indicates alt_cycles_mode)

{

if (DCONm indicates .NOT. alt _cycles_mode

.OR. G0m = 0)

{

if (previous _cycle = instruction-cycle) return 1;

else return 0;

}

else if (previous_cycle = instruction_cycle

.AND. previous_dma_cyle = .NOT. DMAn) return 1;

}

return 0;

end mode_logic (n);

If the channel is configured to External Demand mode, then the first if-condition is not satisfied but the second one is. In that case the block of statements following that if-condition and delim- ited by {...} is executed: if the demand flag (IEO for channel 0 and IE1 for channel 1) is set, the “return 1” expression is executed and the remainder of the function is not. If the demand flag is not set, the “return 0” expression is executed and the remainder of the function is not.

If the channel is configured to Serial Port Demand mode, the source and destination addresses, SARn and DARn, have to be checked to see which Serial Port buffer is being addressed, and whether its demand flag is set.

SARn refers to the 16-bit source address for “this channel”. Note that the condition “SARn = SBUF” cannot be true unless the SAS and IAS bits in DOCNn are configured to select SFR space. If SARn is numerically equal to the address of SBUF(99H), and SAS and ISA are configured to select internal RAM rather than SFR space, then SARn refers to location 99H in the “upper 128” of internal RAM, not to SBUF.

Kawasaki LSI USA, Inc.

Page 88 of 120

Ver. 0.9 KS152JB2

Page 88
Image 88
Kawasaki 80C152, 80C51 technical specifications Kawasaki LSI USA, Inc Ver .9 KS152JB2