
Rev. 0
|
Page 2  of 44
|
March 2006
ADSP-21261
ADDITIONAL KEY FEATURES
1M bit on-chip dual-ported SRAM (0.5M bit block 0, 0.5M bit 
block 1) for simultaneous access by core processor and 
DMA
3M bit on-chip dual-ported mask-programmable ROM 
(1.5M bit in block 0 and 1.5M bit in block 1)
Dual data address generators (DAGs) with modulo and bit-
reverse addressing
Zero-overhead looping with single-cycle loop setup, 
providing efficient program sequencing
Single-instruction, multiple-data (SIMD) architecture 
provides:
Two computational processing elements
Concurrent execution—each processing element executes 
the same instruction, but operates on different data 
Parallelism in buses and computational units allows single 
cycle executions (with or without SIMD) of a multiply 
operation; an ALU operation; a dual memory read or 
write; and an instruction fetch
Accelerated FFT butterfly computation through a multiply 
with add and subtract instruction
DMA controller supports:
18 zero-overhead DMA channels for transfers between the 
ADSP-21261 internal memory and serial ports (eight), 
the input data port (IDP) (eight), the SPI-compatible port 
(one), and the parallel port (one) 
32-bit background DMA transfers at core clock speed, in 
parallel with full-speed processor execution
JTAG background telemetry for enhanced emulation 
features
IEEE 1149.1 JTAG standard test access port and on-chip 
emulation
Dual voltage: 3.3 V I/O, 1.2 V core
Available in 136-ball BGA and 144-lead LQFP packages
Also available in lead-free packages
Digital applications interface includes four serial ports, two 
precision clock generators, an input data port, three pro-
grammable timers, and a signal routing unit 
Asynchronous parallel/external port provides:
Access to asynchronous external memory
16 multiplexed address/data lines that can support 24-bit 
address external address range with 8-bit data or 16-bit 
address external address range with 16-bit data
50M byte/s transfer rate for 150 MHz core rate
256 word page boundaries
External memory access in a dedicated DMA channel
8-bit to 32-bit and 16-bit to 32-bit word packing options
Programmable wait state options: 2 to 31 CCLK
Serial ports provide:
Four dual data line serial ports that operate at up to 
37.5M bit/s for a 150 MHz core on each data line—each 
has a clock, frame sync, and two data lines that can be 
configured as either a receiver or transmitter pair
Left-justified sample-pair and I
2
S support, programmable 
direction for up to 16 simultaneous receive or transmit 
channels using two I
2
S-compatible stereo devices per 
serial port
TDM support for telecommunications interfaces including 
128 TDM channel support for newer telephony inter-
faces such as H.100/H.110
Up to 12 TDM stream support, each with 128 channels 
per frame
Companding selection on a per channel basis in TDM mode
Input data port provides an additional input path to the 
SHARC core configurable as either eight channels of I
2
S or 
serial data or as seven channels plus a single 20-bit wide 
synchronous parallel data acquisition port
Supports receive audio channel data in I
2
S, left-justified 
sample pair, or right-justified mode
Signal routing unit (SRU) provides configurable and flexible 
connections between all DAI components, four serial 
ports, two precision clock generators, three timers, an 
input data port/parallel data acquisition port, 10 inter-
rupts, six flag inputs, six flag outputs, and 20 SRU I/O pins 
(DAI_Px)
Serial peripheral interface (SPI)
Master or slave serial boot through SPI 
Full-duplex operation
Master-slave mode multimaster support
Open-drain outputs
Programmable baud rates, clock polarities, and phases
3 Muxed Flag/IRQ lines
1 Muxed Flag/Timer expired line
ROM-based security features:
JTAG access to memory permitted with a 64-bit key
Protected memory regions that can be assigned to limit 
access under program control to sensitive code
PLL has a wide variety of software and hardware multi-
plier/divider ratios