MOS Technology TED

The video capabilities provided by the TED were largely a subset of those in the VIC-II. The TED supported five video modes:[1]

• Text mode of 40×25 characters with 8×8 pixels
• Multicolor text (4×8 pixels per character, double pixel width in the x-direction)
• Extended background color mode (8×8 pixels per character)
• Multicolor Graphics 160×200 pixels
• Hi-Res Graphics 320×200 pixels
• 46μs of the 52μs long visible part of the scan lines is filled with pixels

These were largely unchanged from the corresponding VIC-II modes aside from different register and memory mapping (see the article on the VIC-II for information on graphics modes). However, the TED lacked the sprite capabilities of the VIC-II, and so game animation had to be done with programmable characters like on the VIC-20. This tended to restrict the graphics of C16/Plus 4 games versus the C64. The sprites used 2/3 of the die area of the VIC-II pushing the transistor count over that of the CPU. Reduction to one sprite (for cursor or mouse pointer or player) would have reduced this area by eight acceptable for a computer supposed to be cheaper than the C64. TED caches the color attributes on-chip increasing the SRAM from 40 bytes to 75 bytes and does away with the external color RAM.

The TED did include two features that the VIC-II lacked: luminance control and blinking text. Fifteen of its 16 colors (black being the exception) could be assigned one of 8 luminance values, thus making the TED capable of displaying a far wider array of colors than the VIC-II. The full palette of 121 colors is shown below.[2]

hue / luminance	0	1	2	3	4	5	6	7
1 — black	1,0	1,1	1,2	1,3	1,4	1,5	1,6	1,7
2 — white	2,0	2,1	2,2	2,3	2,4	2,5	2,6	2,7
3 — red	3,0	3,1	3,2	3,3	3,4	3,5	3,6	3,7
4 — cyan	4,0	4,1	4,2	4,3	4,4	4,5	4,6	4,7
5 — purple	5,0	5,1	5,2	5,3	5,4	5,5	5,6	5,7
6 — green	6,0	6,1	6,2	6,3	6,4	6,5	6,6	6,7
7 — blue	7,0	7,1	7,2	7,3	7,4	7,5	7,6	7,7
8 — yellow	8,0	8,1	8,2	8,3	8,4	8,5	8,6	8,7
9 — orange	9,0	9,1	9,2	9,3	9,4	9,5	9,6	9,7
10 — brown	10,0	10,1	10,2	10,3	10,4	10,5	10,6	10,7
11 — yellow-green	11,0	11,1	11,2	11,3	11,4	11,5	11,6	11,7
12 — pink	12,0	12,1	12,2	12,3	12,4	12,5	12,6	12,7
13 — blue-green	13,0	13,1	13,2	13,3	13,4	13,5	13,6	13,7
14 — light blue	14,0	14,1	14,2	14,3	14,4	14,5	14,6	14,7
15 — dark blue	15,0	15,1	15,2	15,3	15,4	15,5	15,6	15,7
16 — light green	16,0	16,1	16,2	16,3	16,4	16,5	16,6	16,7

As more accurate color values inside color palette table is shown below:

		luma #	0	1	2	3	4	5	6	7
		Y	0.125	0.25	0.375	0.5	0.625	0.75	0.875	1
hue #	Pb (rel.)	Pr (rel.)	.	.	.	.	.	.	.	.
0 — black	0	0	0,0	0,1	0,2	0,3	0,4	0,5	0,6	0,7
1 — white	0	0	1,0	1,1	1,2	1,3	1,4	1,5	1,6	1,7
2 — red	−0.3826834	0.9238795	2,0	2,1	2,2	2,3	2,4	2,5	2,6	2,7
3 — cyan	0.3826834	−0.9238795	3,0	3,1	3,2	3,3	3,4	3,5	3,6	3,7
4 — purple	0.7071068	0.7071068	4,0	4,1	4,2	4,3	4,4	4,5	4,6	4,7
5 — green	−0.7071068	−0.7071068	5,0	5,1	5,2	5,3	5,4	5,5	5,6	5,7
6 — blue	1	0	6,0	6,1	6,2	6,3	6,4	6,5	6,6	6,7
7 — yellow	−1	0	7,0	7,1	7,2	7,3	7,4	7,5	7,6	7,7
8 — orange	−0.7071068	0.7071068	8,0	8,1	8,2	8,3	8,4	8,5	8,6	8,7
9 — brown	−0.9238795	0.3826834	9,0	9,1	9,2	9,3	9,4	9,5	9,6	9,7
10 — yellow-green	−0.9238795	−0.3826834	10,0	10,1	10,2	10,3	10,4	10,5	10,6	10,7
11 — pink	0	1	11,0	11,1	11,2	11,3	11,4	11,5	11,6	11,7
12 — blue-green	0	−1	12,0	12,1	12,2	12,3	12,4	12,5	12,6	12,7
13 — light blue	0.7071068	−0.7071068	13,0	13,1	13,2	13,3	13,4	13,5	13,6	13,7
14 — dark blue	0.9238795	0.3826834	14,0	14,1	14,2	14,3	14,4	14,5	14,6	14,7
15 — light green	−0.3826834	−0.9238795	15,0	15,1	15,2	15,3	15,4	15,5	15,6	15,7

The TED featured a simple tone generator that produced two channels of audio. The first channel produced a square wave, and the second could produce either a square wave or white noise. Between the two channels you could hear either two tones or one tone plus noise. This tone generator was designed for business applications, and did not provide the extensive sound features found in the SID chip.

The TED includes three 16-bit interval timers, which consist of down counters operating at the master clock frequency. They can generate IRQs on underflow. The chip also contains an I/O port, which is used on the Plus/4 and 16 to scan the keyboard and joystick. In addition, it handles bank switching, used by the operating system to maximize the amount of RAM available to Commodore BASIC.

TED has a higher priority on DRAM access than the CPU. Thus in the borders the CPU is able to run at full speed, but in the active display area it is throttled down to half the clock rate. An undesirable feature of the chip is its well-known tendency to destroy itself through overheating. To preserve a computer which employs this chip in working order, it is recommended to improve its cooling.[3]

• Talking to TED: The MOS 7360/8360 Text Display ICs
• Commodore plus/4 Hardware Manual