The basic idea is to use the chip's hardware as far as possible. The SPI module generates video bits. The PWM (or Counter) module generates Sync pulses.
3 external components (resistor matrix for DAC),
compliance with CCIR (PAL/SECAM),
resolution 128 x 72 pixels (16 chars per line, 9 lines of text)
displayed text is located in buffer (144 bytes of RAM),
on-the-fly symbol generator,
96 symbols in set
Fig.1 TV screen
Download the project (60 KB) for PSoC Designer 4.2
1. The main code generating the video signal is located in counter8_1int.asm
2. SCBLOCK_1 User Module is placed only for experiments
3. This project uses the Internal Main Oscillator (accuracy +/- 2%)
4. The structure of Vertical Sync pulse is simplified
5. 624 video lines per frame are used (instead of 625 in PAL/SECAM)
1. The advanced algorithm is used in commercial IC, SV2000, that is available on http://www.speechchips.com. This video IC receives a text and commands from UART (direct connection to COM is also supported) and generates a PAL/SECAM/ NTSC video. Additional features are: loadable sets of fonts, a text and mode are saved and restored by special commands, a hardware cursor is implemented, etc... Free communication application (164K, font examples are also included) can be used for fast prototyping and learning the command set ("as is", without warranties, tested under Win98).
2. Are your still not ARMed? The same idea is realized in my ARM-based project. For details, read my article "TV-Based Oscilloscope" in Circuit Cellar magazine, Issue 196, or download the entry AR1755.zip (1 MB) from the Philips ARM Design Contest 2005. The implemented video generator has a resolution 512 x 256 pixels (true graph mode) and operates as a background task.
Created: 01/06/2005. Updated: 04/23/2008.