GENERAL DESCRIPTION
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.

FEATURES
PCF84CXXXA kernel
• 8-bit CPU, ROM, RAM, I/O and derivative logic in one package
• Over 80 instructions
• All instructions of 1 or 2 cycles
• Quasi-bidirectional standard I/O port lines (P0, P1)
• Configuration of I/O lines individually selected by mask
• External interrupt INT/T0
• 2 direct testable inputs T0, T1
• 8-bit timer/event counter
• Single level vectored interrupt: external (INT), counter/timer, I2C-bus and VSYNC
• Configuration of optimal on-chip oscillator transconductance by mask
• On-chip oscillator clock frequency: 1 to 10 MHz
• Power-on-reset and low-voltage detector
• Low standby voltage and current in Idle and Stop modes
• Single power supply: 4.5 to 5.5 V
• Operating temperature: −20 to +70 °C.

VST and OSD derivative
• 6 kbytes (PCA84C646) or 8 kbytes (PCA84C846) system ROM, 192 bytes system RAM
• A multi-master I2C-bus interface
• One 14-bit PWM output for VST
• Three AFC inputs with 4-bit DAC and comparator
• Four 6-bit PWM and four 7-bit PWM outputs (DACs for analog controls)
• Eight port lines with 10 mA LED drive (at ≤1.2 V) capability
• Programmable active level polarities of VSYNC/HSYNC
• Display RAM: 64 × 10-bit
• Display character fonts: 64 (62 customized + 2 special reserved codes)
• Display starting position: 64 different positions by software control, both vertical and horizontal
• Character size: 4 different character sizes, line-by-line basis, 1 dot = 1H/1V, 2H/2V, 3H/3V, 4H/4V. (H: OSD clock period, V: number of horizontal scan line height)
• Character matrix: 12 × 18 with no spacing between characters
• Foreground colours: 8, character-by-character basis
• Background colours: 8, word-by-word basis. Available when background is either in North-west shadowing, Box shadowing and Frame shadowing mode
• Background/shadowing modes: 4, No background, North-west shadowing, Box shadowing, Frame shadowing (raster blanking), frame basis
• On-chip oscillator for On Screen Display (OSD) function
• Character blinking rate: 1 : 1, 1 : 3, 3 : 1 (frequency: 1⁄16, 1⁄32, 1⁄64 or 1⁄128 of fVSYNC, programmable), character basis
• Display format: flexible display format by using Carriage Return (CR) code
• Spacing between lines: 4 different choices, from 0, 4, 8 or 12 horizontal scan lines
• Auto display character RAM address post increment when writing data
• On-chip Power-on-reset
• VSYNC leading edge can generate interrupt (programmable enable/disable by software)
• 8-bit counter triggered by external pulse input.