APPENDIX
IC DESCRIPTION
5-1. ST92195
(1) General Description
1.1 INTRODUCTIONthe CPU and its peripherals stop operation and the I/O
The ST92195 microcnontoller is developed and manufac-ports enter high impedance mode. A reset is necessary to
tured by STMicroelecrtonics using a proprietary n-well exit from Halt mode.
HCMOS process. Its performance derives from the use of 1.1.3 I/O Ports
a flexible 256-register programming model for ultra-fast Up to 28 I/O lines are dedicated to digital Input/Output.
context switching and real-time event response. The intel-These lines are grouped into up to five I/O Ports and can
ligent onchip peripherals offload the ST9 core from I/O be configureed on a bit basis under software control to pro-
and data management processing tasks allowing critical vide timing, status signals, timer and output, analog inputs,
application tasks to get the maximum use off core external interrupts and serial or parallel I/O.
resources. The ST92195 MCU supports low power con-1.1.4 TV Peripherals
sumption and low voltage operation for power-efficient A set of on-chip peripherals form a complete system for TV
and low-cost embedded systems.set and VCR applications:
1.1.1 ST9+Core- Voltage Synthesis
The advanced Core consists of the Central Processing - VPS/WSS Slicer
Unit (CPU), the Register File and the Interrupt controller.- Teletext Slicer
The general-purpose registers can be used as accumula-- Teletext Display RAM
tor, Index register, or address pointers. Adjacent register - OSD
pairs make up 16-bit registers for addressing or 16-bit 1.1.5 On Screen Display
processing. Although the ST9 has an 8-bit ALU, the chip The human interface is provided by the On Screen Display
handles 16-bit operations, including arithmetic, loads/module, this can produce up to 26 lines of up to 80 charac-
stores, and memory/register and memory/memory ters from a ROM defined 512 character set. The character
exchanges. Two basic memory spaces are available : resolution is 10x10 dot. Four character sizes are sup-
Program Memory and the Register File, Which includes ported. Serial attributes allow the user to select foreground
the control and status registers of the on-chip peripherals.and background. Parallel attributes can be used to select
1.1.2 Power Saving Modesadditional foreground and background colors and underline
To optimize performance versus power consumption, a on a character by character basis.
range of operating modes can be dynamically selected.1.1.6 Teletext and Display RAM
Run Mode. This is the full speed execution mode with The internal 8k Teletext and Display storage RAM can be
CPU and peripherals running at the maximum clock used to store Teletext pages as well as Display parame-
speed delivered by the phase Locked Loop(PLL) of the ters.
Clock Control Unit(CCU).1.1.7 Teletext, VPS and WSS Data Slicers
Wait For Interrupt Mode. The Wait For Inter-The three on-board data slicers using a single external
rupt(WFI) instruction suspends program execution until crystal are used to extract the Teletext, VPS and WSS
information from the video signal. Hardware Hamming
an interrupt request is acknowledged. During WFI, the
CPU clock is halted while the peripheral and interrupt decoding is provided.
controller keep running at a frequency programmable via 1.1.8 Voltage Synthesis Tuning Control
the CCU. In this mode, the power consumption of the 14-bit Voltage Synthesis using the PWM (Pulse Width
Modulation)/BRM (Bit Rate Modulation) technique can be
device can be reduced by more than 95%(LP WFI).
Wait For Interrupt Mode. The Wait For Inter-used to genetate tuning voltages for TV set applications.
rupt(WFI) instruction, and if the Watchdog is not enable, The tuning voltage is output on one of two separate output
pins.
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ACEC
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