Cast C6845
The C6845 Cathode Ray Tube Controller (CRTC) interfaces a microprocessor to a raster-scan CRT display. The C6845 is a synchronous, synthesizable VHDL megafunction, functionally equivalent to the Motorola MC6845 CRT Controller. The microprocessor access 19 registers (1 Address and 18 Data Registers) within the C6845 in order to provide video timing, refresh memory addresses, cursor, and light pen strobe signals.GENERAL DESCRIPTION
CRT video timing signals include Vertical Sync (VS), Horizontal Sync (HS), and Display Enable (DE) output signals. Refresh memory addressing includes Memory Address (MA[13:0]) and Row Address (RA[4:0]) output buses. The C6845 microprocessor interface consist of unidirectional data input (DIN[7:0]) and data output (DOUT[7:0]) buses and control signals RS, RWn, CSn, and E. Optionally, an available bus wrapper converts the unidirectional data buses into an 8-bit bi-directional data bus (D[7:0]). This is the pin equivalent to the MC6845.FEATURES
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● Fully-synchronous, synthesizable VHDL Megafunction, functionally equivalent to Motorola MC6845 Capable of driving alphanumeric, semi-graphic, or bit-mapped graphics displays Wide range of programmable alphanumeric screen formats Programmable registers controlling output signals Vertical Sync (VS), Horizontal Sync (HS), and Display Enable (DE) signals Programmable horizontal line rate and sync pulse wid...