Pin function descriptions, Adsp-ts201s – Analog Devices TigerSHARC ADSP-TS201S User Manual
Page 12
Rev. C
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Page 12 of 48
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December 2006
ADSP-TS201S
PIN FUNCTION DESCRIPTIONS
While most of the ADSP-TS201S processor’s input pins are nor-
mally synchronous—tied to a specific clock—a few are
asynchronous. For these asynchronous signals, an on-chip syn-
chronization circuit prevents metastability problems. Use the ac
specification for asynchronous signals when the system design
requires predictable, cycle-by-cycle behavior for these signals.
The output pins can be three-stated during normal operation.
The DSP three-states all output pins during reset, allowing these
pins to get to their internal pull-up or pull-down state. Some
pins have an internal pull-up or pull-down resistor (±30% toler-
ance) that maintains a known value during transitions between
different drivers.
Table 3. Pin Definitions—Clocks and Reset
Signal
Type
Term
Description
SCLKRAT2–0
I (pd)
na
Core Clock Ratio. The DSP’s core clock (CCLK) rate = n × SCLK, where n is user-
programmable using the SCLKRATx pins to the values shown in
. These pins
may change only during reset; connect these pins to V
DD_IO
or V
SS
. All reset specifica-
must be satisfied. The core clock rate (CCLK)
is the instruction cycle rate.
SCLK
I
na
System Clock Input. The DSP’s system input clock for cluster bus. The core clock rate
is user-programmable using the SCLKRATx pins.
For more information, see Clock
RST_IN
I/A
na
Reset. Sets the DSP to a known state and causes program to be in idle state. RST_IN
must be asserted a specified time according to the type of reset operation. For details,
see
, and
.
RST_OUT
O
na
Reset Output. Indicates that the DSP reset is complete. Connect to POR_IN.
POR_IN
I/A
na
Power-On Reset for internal DRAM. Connect to RST_OUT.
I = input; A = asynchronous; O = output; OD = open-drain output; T = three-state; P = power supply; G = ground; pd = internal pull-down
5 k
Ω
; pu = internal pull-up 5 k
Ω
; pd_0 = internal pull-down 5 k
Ω
on DSP ID = 0; pu_0 = internal pull-up 5 k
Ω
on DSP ID = 0; pu_od_0 = internal
pull-up 500
Ω
on DSP ID = 0; pd_m = internal pull-down 5 k
Ω
on DSP bus master; pu_m = internal pull-up 5 k
Ω
on DSP bus master; pu_ad
= internal pull-up 40 k
Ω
. For more pull-down and pull-up information, see
Electrical Characteristics on Page 22
Term (termination of unused pins) column symbols: epd = external pull-down approximately 5 k
Ω
to V
SS
; epu = external pull-up approx-
imately 5 k
Ω
to V
DD_IO
, nc = not connected; na = not applicable (always used); V
DD_IO
= connect directly to V
DD_IO
; V
SS
= connect directly to V
SS
Table 4. SCLK Ratio
SCLKRAT2–0
Ratio
000
(default)
4
001
5
010
6
011
7
100
8
101
10
110
12
111
Reserved