CRT9006-83 Datasheet | SMSC

STANDARD MICROSYSTEMS CORPORATIONAt CRT 9006-135 CRT 9006-83 J.1PC FAM ILY Single Row Buffer SRB Features : D Low Cost Solution to CRT Memory Contention Problem D Provides Enhanced Processor Throughput for CRT Display Systems D Provides 8 Bit Wide Variable Length Serial Memory D Permits Active Video on All Scan Lines of Data Row D Dynamically Variable Number of Characters per Data Row- ... 64,80, 132, ... up to a Maximum of 135 D Cascadable for Data Rows Greater than 135 Characters D Stackable for Invisible Attributes or Character Widths of Greater than 8 Bits D Three-State Outputs D 4MHz Typical Read/Write Data Rate D Static Operation D patible with SMC CRT 5037, CRT 9007, and other CRT Controllers D 24 Pin Dual In Line Package D +5 Volt Only Power Supply D TTL patible Inputs and Outputs D Available in 135 Byte Maximum Length (CRT 9006-135) or 83 Byte Maximum Length (CRT 9006-83) PIN CONFIGURATION DOUT3 DOUT2 DOUTl DOUT0 CLK WREN CIRCNT CKEN DIN0 DINl DIN2 DIN3 GND DOUT4 DOUT5 DOUT6 DOUT7 OF DIN? DIN6 DIN5 DIN4 +5V Package: 24-pin D.I.P. APPLICATIONS: D CRT Data Row Buffer D Block-Oriented Buffer D Printer Buffer D Synchronous munications Buffer D Floppy Disk Sector Buffer GENERAL DESCRIPTION The SMC Single Row Buffer (SRB) provides a low cost solution to memory contention between the system processor and CRT controller in video display systems. The SRB is a RAM-based buffer which is loaded with character data from system memory during the first scan line of each data row. While data is being written into the RAM it is also being output through the multiplexer onto the Data Ouput (DOUT) Lines. During subsequent scan lines in the data row, the system will disable Write Enable (WREN) and cause data to be read out from the internal RAM for CRT screen refresh, thereby releasing the system memory for processor access for the remaining N-1 scan lines where N is the number of scan lines per data row. The SRB enhances processor throughput and...