cx25840 Conexant Systems, Inc., cx25840 Datasheet - Page 98

• Manufacturer Part Number: cx25840
• Description: Video Decoder And Broadcast Audio
• Manufacturer: Conexant Systems, Inc.

Detailed Functional Description
3.13
3.14
3.14.1
3-72
Table 3-32. Default PRGM[0:7] Pin Configuration
DVALID/PRGM0
FIELD/PRGM1
HRESET/PRGM2 HRESET
VRESET/HCTL/
PRGM3
IRQ_N/PRGM4
IR_TX/PRGM6
IR_RX/PRGM5
PLL_CLK/PRGM7 GPO[3]
GPIO[0]/PRGM8
GPIO[1]/PRGM9
Pin Name
Output Select
DVALID
FIELD
VRESET
IRQ_N
IR_TX
GPO[2]
GPO[0]
GPO[1]
Output Pin Configuration
Hardware Interrupt
I/O Pin Configuration
Default
The interrupt pin, IRQ_N/PRGM4 (VIRQ_N in VIP mode) signals interrupt
conditions that occur within the chip. An interrupt condition can be enabled through
the Interrupt Mask 1 and Interrupt Mask 2 (0x412 and 0x413) register. Setting the
appropriate video decoder or IR controller bits in the register masks the assertion of
the interrupt pin. The Interrupt Status 1 and Interrupt Status 2 (0x410 and 0x411)
registers allow the status of each of those interrupts to be checked separately. There is
also an option to invert the polarity of the pin.
The digital I/O pin functionality is extremely flexible. The CX25840/1/2/3 provides
up to eleven programmable pins. These configurable GPIOs are shared with the
following pin/port groups so that the user can assign exactly which pins can be
dedicated to specific functions versus general purpose I/O functions.
Any of the programmable pins can be configured to provide alternate functions from
their default state. This allows customization of the output interface in order to fit a
wide variety of system requirements.
programmable pins after reset.
Video Timing Control (VRESET/HCTL/PRGM3 is unavailable when VIP Host
mode is selected)
Interrupt pin
Infrared Remote Transmit
Infrared Remote Receive
Auxiliary PLL Output Clock
Default function is a valid pixel data indicator. When asserted, indicates a valid pixel. Can be
programmed for alternate functions in
Default function is field indicator. Even/Odd Field indicator (0 = odd field, 1 = even field). Field
resets to 0, odd, and toggles every new_field. Can be programmed for alternate functions in
Table
Default function is horizontal reset indicator. Asserted at 0H sync point, held for 32 or 64 clocks.
Width can be configured through HR32 bit in MISC_TIM_CTRL register in video decoder core.
Can be programmed for alternate functions in
Default function is vertical reset indicator. Asserted from vsync begin (start of serration pulses)
through end of equalization pulse period, nominally 5 or 6 lines depending on video standard.
Can be programmed for alternate functions in
Interface Reset Input and is not programmable.
Interrupt pin
Infrared Remote Transmit
Infrared Remote Receive. This is by default an input, so the output select will be a don’t care
unless put in output mode.
Auxiliary PLL output clock. This default mode is to select the PLL output from inside the analog
domain, so this output select will be a don’t care unless CLK_PAD_IN is selected from the digital
core.
Configurable Multifunction Status/Control Pins
Configurable Multifunction Status/Control Pins
3-33.
Conexant
Table
Table 3-32
Description
3-33.
Table
Table
3-33. In VIP mode this pin becomes the Host
3-33.
shows the default state of the
CX25840/1/2/3 Data Sheet
102284B
8/3/05