MICROCHIP CRT8021H-031

The SMC CRT 8021 Video Attribute Controller (VAC) is an n-channel COPLAMOS MOS/LSI device. It contains wide graphics and fine graphics logic, attribute logic, data latches, field and character attribute latches, a blinking cursor, and a high-speed video shift register. The CRT 8021 VAC is a companion device to SMC's CRT 5027/37 VTAC or CRT 9007 VPAC. Combined with a character ROM and either the CRT 5027/37 or CRT 9007, the CRT 8021 forms the primary circuitry required for the video display section of a CRT video terminal. The CRT 8021 video output can be directly connected to the CRT monitor video input. The blanking output of the CRT 5027/37 or CRT 9007 can be directly connected to the retrace blanking input of the CRT 8021 to provide horizontal and vertical retrace blanking of the video output. The CRT 8021 features a blinking cursor with an independent cursor blink rate that is twice the character blink rate, with a 50/50 duty cycle. CRT 8021 attributes include: reverse video, character blanking, blink, underline, and strikethrough. The character blink rate has a 75/25 duty cycle. Underline and strikethrough are similar but independently controllable functions; these attributes are available in all modes. Fine graphics mode enables users to create single-line drawings and tables. In wide graphics mode, the CRT 8021 generates a graphics entity the same size as the character block, consisting of 8 sections, each associated with one bit of a graphics byte, providing 256 unique graphic symbols. The CRT 8021 can therefore generate alphanumeric characters or various graphics entities depending on the selected mode, which can be changed on a per-character basis. The CRT 8021 is available in two versions. The CRT 8021 provides an eight-section graphics entity that fills the character block, designed for 7-dot wide, 9- or 11-dot high characters in 9×12 or 10×12 character blocks. The CRT 8021-003 provides a six-section graphics entity for 5×7 or 5×9 characters in character blocks of up to 7×10 dots.

• On-chip video shift register
• Maximum shift register frequency: 20MHz
• Maximum character clock rate: 2.5MHz
• On-chip horizontal and vertical retrace video blanking
• On-chip graphics generation
• On-chip attribute logic — character, field
• Reverse video
• Character blanking
• Character blinking
• Underline
• Strikethrough
• On-chip blinking cursor
• On-chip data buffer
• On-chip attribute buffer
• +5V operation
• TTL compatible
• MOS N-channel silicon-gate COPLAMOS process
• Pin compatible with CRT 5027/37 VTAC and CRT 9007 VPAC