2/24/2008 9T6WP
Preliminary Hardware Data Module
BCM7405
06/29/07
Functional Description
Bro a d c o m Co rp o r a ti o n
Document
7405-1HDM00-R
Peripherals Page 1-71
P
ERIPHERALS
O
VERVIEW
The BCM7405 provides common peripherals used for set-top box control. In addition, there is an external bus interface to
support connection of external devices like SRAM and flash memories. The BCM7405 also has several advanced
connectivity features including Ethernet, Serial ATA, and USB.
P
ERIPHERAL
C
ONTROL
U
NIT
The peripheral control unit within the BCM7405 contains the following peripherals:
•
Infrared (IR) Blaster
•
IR Keyboard/Remote Receiver
•
UHF Remote Control Receiver
•
Three UARTS
•
Keypad/LED controller
•
Many General-Purpose I/O (GPIO) pins
•
Master SPI Controller
•
Modified SPI for Open Cable support
•
Four Master BSC Controllers
•
Slave BSC Controller
•
Two Smart Card Interfaces
•
Two PWM generators
•
Four programmable timers and one watchdog timer
K
EYPAD
C
ONTROLLER
The keypad controller notifies the microcontroller whenever it detects that a key has pressed via an interrupt. When the
processor responds to the interrupt, the scan code of the key(s) detected is reported to the processor.
LED C
ONTROLLER
The CPU sends data (such as current channel being viewed, time of day, diagnostic codes, and IR receiver active) to the
LED controller which is responsible for processing this data, and driving the four 7-segment LED elements and a bank of
discrete LEDs.
IR R
ECEIVER
C
ONTROLLER
The IR receiver controller processes the IR pulses to determine which key code data was sent from the user's remote. The
processor is notified of IR data reception via an interrupt, and the logic passes on the key code or repeat data when the
processor acknowledges the interrupt.
The BCM7405 contains two identical and independent IR Receiver modules. Each receiver can receive signals from a device
using Sejin, TWIRP, or one of two proprietary protocols denoted Remote A and Remote B. A programmable Consumer IR
decoder is also available to decode transmissions that use pulse position modulation, pulse width modulation, or bi-phase
