Conexant CX2388x

A PCI interface chipset family of ICs from Conexant. The CX2388x are the direct successor to the Fusion 878A chip.

The CX2388x chips are supported under Linux, by the cx88 and associated kernel driver modules, however, there are areas of the chip's feature set that the drivers currently lack support for or either need improvement upon (see Cx88 devices current status section for more information).

Overview/Features

These chips provide a/v decoder functionality and have dedicated DVB support in a new PCI function, as opposed to the hackish approach employed by its predecessor, the 878A; which provided DVB support via use of the chip's digital audio input lines.

In fact, the CX2388x chips have 6 (?) PCI functions, but fortunately they all share the same (huge 16MB!) memory mapping. Executing the command lspci will reveal in it's output that the cx2388x has the following ports:

00:09.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder (rev 05)
00:09.1 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder [Audio Port] (rev 05)
00:09.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder [MPEG Port] (rev 05)
00:09.4 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder [IR Port] (rev 05)

The chips have the same (identical?) RISC programs as the Bt878 and the same kind of I²C bus control controller.

Analog Functions

Analog video inputs

In terms of its analog to digital signal processing capabilities, the cx2388x brings some improvements over the older Fusion 878A chipset.

Like many other contemporary mainstream A/V decoders, the maximum capture window that these chips support is "up to 768 x 576 (square pixel PAL/SECAM)".

Analog audio inputs

The cx2388x family of ICs are capable of providing demodulation of all major global broadcast audio standards. In other words, they can directly accept S-IF from a TV tuner pll. These signals will in turn be decoded and are output either to the PC's sound card directly via a patch cable (invokes a DAC step), to a digital audio output interface (eg. SPDIF), or to the host via a DMA channel.

The cx2388x IC's do NOT process other analog audio sources. They do, however, provide the ability to connect directly, via an i2s input port, to a 3rd party audio ADC.

External Links

• Conexant cx2388x product page
  • Spec Sheet.