2/24/2008 9T6WP
BCM7405
Preliminary Hardware Data Module
Functional Description
06/29/07
Bro a d c o m C o rp o r a ti o n
Page 1-28
Broadcom Security Processor
Document
7405-1HDM00-R
The PCR module also is used to aid in the detection of unmarked PCR discontinuities. The module monitors the PCR base
error (which already exists in the PCR tb_loop module). The module checks the resulting base error for each received PCR
against the programmable threshold, which is a 32-bit value with a default of 255 and has units of 27/300 MHz for MPEG
mode. If the threshold is exceeded one time, the one_pcr_error_interrupt is asserted. If the threshold is exceeded twice in a
row, the two_pcr_error_interrupt is asserted. The two_pcr_error_interrupt is provided so that single PCR errors can be
ignored. Both interrupts are maskable. Since the base error can be both positive and negative, the approximate absolute
value of the base error is compared to the threshold.
In addition to extracted PCRs from the transport stream, the PCR block can lock Timebase outputs to one of following
timebase references (asynchronous to internal system clock).
•
I
2
S 0
•
656 Hsync0
•
656 Vsync0
•
656 Fsync0
The time-base reference is muxed at input level of LOOP control, it avoids generation of abrupt frequency change affected
by VCXO control changes during channel change (e.g., digital to analog).
Serial STC Broadcast Module
Data transport supports a global STC counter and a broadcast STC serially to Audio/Video decoders. Also, STC Broadcast
block generates PCR_OFFSET for arrival of each PCR, which is used by audio/video decoders for PTS time management.
B
ROADCOM
S
ECURITY
P
ROCESSOR
The Broadcom Security Processor (BSP) enables Set-Top Box (STB) chips with strong security for high performance
multimedia applications that deal with high-quality video and audio. These applications can range from single-purpose
conditional-access (CA) for watching-TV-only STB to multi-purpose copy-protection (CP) for Personal Video Recorder
(PVR) STB and digital right management (DRM) for multimedia gateway system. Broadcom Security system implements
various security components required in satellite and cable STBs and various CA and CP standards, such as CP for
CableCard and Secure Video Processor (SVP), but its orientation around a powerful Broadcom Security Processor (BSP)
makes it capable of implementing a variety of security algorithms, whether open or proprietary. More than just an integration
of STB security components together, Broadcom Security System design is an integrated security system controlled by BSP
with a small real-time OS kernel that runs on its own master processor. The Broadcom Security Processor (BSP) supports
various security features in an integrated STB SoC system such as:
•
BSP includes One-Time Programmable Non-Volatile Memory (OTP NVM) security module. This module allows unique
keys and various security features and restrictions to be permanently programmed into a chip.
•
BSP can provide key generation and management to the conditional access descramblers, e.g., DVB, DES
descramblers for removing conditional access encryption from incoming transport streams.
•
BSP can provide key generation and management to the mem-to-mem scramblers/descramblers, for PVR copy
protection and other applications.
•
BSP can provide protection to keys required by the interface security modules, e.g., High-bandwidth Digital content
Protection (HDCP) engine for high-bandwidth secure interface to digital displays.
•
BSP can provide access control of various interfaces, e.g., remux interface.
•
BSP can provide a secure environment and hardware acceleration for scrambling and descrambling the external data
with algorithm such as DES/3DES, AES, RS, and DH algorithms, etc.
•
BSP can provide a secure environment for generating and verifying digital signatures, e.g., using RSA and DSA.
