Z90251 Datasheet, PDF (15/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
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1.2 Single-Purpose Pin Descriptions
Table 2 lists the single-purpose pin acronyms, pin names, and descriptions.
Table 2 Single-Purpose Pin Descriptions
Acronym
AGND
B
Pin Name(s)
Analog Ground
Blue
G
Green
GND
Ground
H_SYNC
IRIN
Horizontal Sync
IR Capture Input
OSDX1, OSDX2 On-Screen Display Dot
Clock Oscillators
P21, P22, P23 Port 2 bits 1 - 3
P40, P42, P43 Port 4 bit 0, bits 2 and 3
P63
Port 6 bit 3
R
RESET
Red
System Reset
Description
Analog Ground
CMOS output of the blue video signal B. Video blue can
be programmed for either polarity.
CMOS output of the green video signal G. Video green
can be programmed for either polarity.
Ground
Input pin for external horizontal synchronization signal
Infrared Remote capture input
These oscillator input and output pins for on-screen
display circuits are connected to an inductor and two
capacitors to generate the character dot clock. The dot
clock frequency determines the character pixel width and
phase synchronized to HSYNC
Bidirectional digital port, configured to read digital data or
to send output to an attached device.
Bidirectional digital port, configured to read digital data or
to send output to an attached device.
P63 input can be read directly at 03H. A negative edge
event is latched to IRQ3. An IRQ3-vectored interrupt
occurs if appropriately enabled. A typical application
places the device in Stop mode when P63 goes Low
(IRQ3 interrupt routine). When P63 subsequently goes
High, a Stop-Mode Recovery is initiated.
CMOS output of the red video signal R. Video red can be
programmed for either polarity.
System reset
PS001301-0800