PCA84C646

The PCA84C646 and PCA84C846 are 8-bit microcontrollers with enhanced OSD and VST functions. The PCA84C646 and PCA84C846 are members of the PCA84C640 CMOS microcontroller family. They include the PCF84CXXXA processor core, 6 or 8 kbytes of ROM and 192 bytes of RAM.

I/O requirements of PCA84C646 are adequately catered for with 13 general purpose bidirectional I/O lines plus 16 function combined I/O lines. One 14-bit PWM analog control, 3 AFC inputs (4-bit DAC + comparator) for VST and four 6-bit and 7-bit PWM analog control outputs are provided.

In addition to all these features a master-slave I2C-bus interface, 2 directly testable lines and an enhanced OSD facility for flexible screen format (maximum of 64 character types) are also provided.

The on-chip Phase-Locked Loop (PLL) oscillator for OSD operation of PCA84C646 considerably reduces the radiation generated by the RC or LC oscillator. An 8-bit timer is integrated on-chip with a 5-bit prescaler. Another 8-bit counter with Schmitt-trigger input is used for clock/timer function
application.

Figure 1 shows the block diagram of the PCA84C646 and PCA84C846.

There are three data formats of PCA84C646 for the display RAM code
1. Character Font Code
2. Carriage Return Code
3. Space Code.

The three data formats of PCA84C646 and their descriptions are shown in Tables 9 to 17. Figure 14 illustrates an example of the timing of FB, R, G, and B pulses when displaying a line of dots stream in a character.

FB = VOB; R = VOW0, G = VOW1; B = VOW2.

Figure 15 shows an example of the screen which includes some Cariage Return and Space codes.