9System Interface
9 – 27
load current will increase power dissipation. Some pins will be in one of
several states depending upon the connection of mode pins. For example,
the ADSP-2171’s HIP data bus pins may be either active or inactive
depending whether a host write is in progress or how the host mode pins
are connected. You must perform a careful analysis of each input and
output pin in order to insure lowest power dissipation.
Some inputs are active but ignored. The state of these inputs does not
matter as long as they are at a CMOS level.
Pin Direction State During Powerdown
RESET I Active
PWD I Active
IRQ2 I Active, latched but not serviced
IRQE I(ADSP-2181) Active, latched but not serviced
IRQL0 I(ADSP-2181) Active, latched but not serviced
IRQL1 I(ADSP-2181) Active, latched but not serviced
MMAP I Active
BR I Active, no response until after powerdown
BG O Driven HIGH unless bus is granted
CLKIN I Input buffer inactive, but XTAL oscillator is active unless XTALDIS bit is set
CLKOUT O Driven HIGH
XTAL O Driven HIGH if XTALDIS set, inversion of CLKIN otherwise
PWDACK O Driven HIGH
PMS O Driven HIGH, high impedance if bus granted
DMS O Driven HIGH, high impedance if bus granted
BMS O Driven HIGH, high impedance if bus granted
IOMS O(ADSP-2181) Driven HIGH, high impedance if bus granted
CMS O(ADSP-2181) Driven HIGH, high impedance if bus granted
RD O Driven HIGH, high impedance if bus granted
WR O Driven HIGH, high impedance if bus granted
ADDR<13:0> O High impedance
DATA<23:0> I Inactive
DATA<23:0> O High impedance
SCLK0 I Active
SCLK0 O Driven to static level if internal, high impedance otherwise
TFS0 I Active if SPORT 0 is enabled
TFS0 O Driven if configured internal or in multichannel mode and SPORT 0
enabled, high impedance otherwise
RFS0 I Active if SPORT 0 is enabled
RFS0 O Driven if configured internal and SPORT 0 enabled, high impedance
otherwise
DR0 I Active if SPORT 0 is enabled
DT0 O Driven if serial port operating. Output may be static or changing depending
upon serial clock, high impedance otherwise
Table 9.9 Pin States During Powerdown (cont. on next page)
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