ADSP-TS101S
Rev. C
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Page 13 of 48
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May 2009
Table 5. Pin Definitions—External Port Bus Controls
Signal
Type
Term
Description
ADDR31–0
1
I/O/T
nc
Address Bus. The DSP issues addresses for accessing memory and peripherals on these pins. In
a multiprocessor system, the bus master drives addresses for accessing internal memory or I/O
processor registers of other ADSP-TS101S processors. The DSP inputs addresses when a host or
another DSP accesses its internal memory or I/O processor registers.
I/O/T
nc
External Data Bus. Data and instructions are received, and driven by the DSP, on these pins.
RD
2
I/O/T (pu
3)
nc
Memory Read. RD is asserted whenever the DSP reads from any slave in the system, excluding
SDRAM. When the DSP is a slave, RD is an input and indicates read transactions that access its
internal memory or universal registers. In a multiprocessor system, the bus master drives RD.
The RD pin changes concurrently with ADDR pins.
Write Low. WRL is asserted in two cases: When the ADSP-TS101S writes to an even address word
of external memory or to another external bus agent; and when the ADSP-TS101S writes to a
32-bit zone (host, memory, or DSP programmed to 32-bit bus). An external master (host or DSP)
asserts WRL for writing to a DSP’s low word of internal memory. In a multiprocessor system, the
bus master drives WRL. The WRL pin changes concurrently with ADDR pins. When the DSP is a
slave, WRL is an input and indicates write transactions that access its internal memory or
universal registers.
Write High. WRH is asserted when the ADSP-TS101S writes a long word (64 bits) or writes to an
odd address word of external memory or to another external bus agent on a 64-bit data bus.
An external master (host or another DSP) must assert WRH for writing to a DSP’s high word of
64-bit data bus. In a multiprocessing system, the bus master drives WRH. The WRH pin changes
concurrently with ADDR pins. When the DSP is a slave, WRH is an input and indicates write
transactions that access its internal memory or universal registers.
ACK
I/O/T
epu
Acknowledge. External slave devices can deassert ACK to add wait states to external memory
accesses. ACK is used by I/O devices, memory controllers, and other peripherals on the data
phase. The DSP can deassert ACK to add wait states to read accesses of its internal memory. The
ADSP-TS101S does not drive ACK during slave writes. Therefore, an external (approximately
10 k
) pull-up is required.
O/T
au
Boot Memory Select. BMS is the chip select for boot EPROM or flash memory. During reset, the
DSP uses BMS as a strap pin (EBOOT) for EPROM boot mode. When the DSP is configured to
boot from EPROM, BMS is active during the boot sequence. Pull-down enabled during RESET
(asserted); pull-up enabled after RESET (deasserted). In a multiprocessor system, the DSP bus
MS1–0
O/T (pu
Memory Select. MS0 or MS1 is asserted whenever the DSP accesses memory banks 0 or 1,
respectively. MS1–0 are decoded memory address pins that change concurrently with ADDR
pins. When ADDR31:26 = 0b000010, MS0 is asserted. When ADDR31:26 = 0b000011, MS1 is
asserted. In multiprocessor systems, the master DSP drives MS1–0.
Type column symbols: A = asynchronous; G = ground; I = input; O = output; o/d = open drain output; P = power supply;
pd = internal pull-down approximately 100 k; pu = internal pull-up approximately 100 k; T = three-state
Term (for termination) column symbols: epd = external pull-down approximately 10 k to VSS; epu = external pull-up approximately 10 k
to VDD-IO, nc = not connected; au = always used.