ADSP-21267SKBCZ-X AD [Analog Devices], ADSP-21267SKBCZ-X Datasheet - Page 10

• Manufacturer Part Number: ADSP-21267SKBCZ-X
• Description: Preliminary Technical Data
• Manufacturer: AD [Analog Devices]

ADSP-21267
PIN FUNCTION DESCRIPTIONS
ADSP-21267 pin definitions are listed below. Inputs identified
as synchronous (S) must meet timing requirements with respect
to CLKIN (or with respect to TCK for TMS, TDI). Inputs iden-
tified as asynchronous (A) can be asserted asynchronously to
CLKIN (or to TCK for TRST). Tie or pull unused inputs to
Table 2. Pin Descriptions
Pin
AD15-0
RD
WR
ALE
FLAG3-0
Type
I/O/T
O
O
O
I/O/A
State During &
After Reset
Three-state with
pull-up enabled
Output only, driven
high
Output only, driven
high
Output only, driven
low
Three-state
PRELIMINARY TECHNICAL DATA
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Rev. PrA | Page 10 of 44 | January 2004
Function
Parallel Port Address/Data. The ADSP-21267 parallel port and its corresponding
DMA unit output addresses and data for peripherals on these multiplexed pins. The
multiplex state is determined by the ALE pin. The parallel port can operate in either
8-bit or 16-bit mode. Each AD pin has a 22.5 K internal pull-up resistor. See
Data Modes on page 13
For 8-bit mode: ALE is automatically asserted whenever a change occurs in the
upper 16 external address bits, A23-8; ALE is used in conjunction with an external
latch to retain the values of the A23-8.
For 16-bit mode: ALE is automatically asserted whenever a change occurs in the
address bits, A15-0; ALE is used in conjunction with an external latch to retain the
values of the A15-0.
To use these pins as flags (FLAG15-0) set (=1) bit 20 of the SYSCTL register and
disable the parallel port. See
map to the flag pins. When used as an input, the IDP Channel0 can use these pins
for parallel input data.
Parallel Port Read Enable. RD is asserted low whenever the DSP reads 8-bit or 16-
bit data from an external memory device. When AD15-0 are flags, this pin remains
deasserted.
Parallel Port Write Enable. WR is asserted low whenever the DSP writes 8-bit or
16-bit data to an external memory device. When AD15-0 are flags, this pin remains
deasserted.
Parallel Port Address Latch enable. ALE is asserted whenever the DSP drives a
new address on the parallel port address pins. On reset, ALE is active high. However,
it can be reconfigured using software to be active low. When AD15-0 are flags, this
pin remains deasserted.
Flag Pins. Each FLAG pin is configured via control bits as either an input or output.
As an input, it can be tested as a condition. As an output, it can be used to signal
external peripherals. These pins can be used as an SPI interface slave select output
during SPI mastering. These pins are also multiplexed with the IRQx and the TIMEXP
signals.
In SPI master boot mode, FLAG0 is the slave select pin that must be connected to
an SPI EPROM. FLAG0 is configured as a slave select during SPI master boot. When
bit 16 is set (=1) in the SYSCTL register, FLAG0 is configured as IRQ0.
When bit 17 is set (=1) in the SYSCTL register, FLAG1 is configured as IRQ1.
When bit 18 is set (=1) in the SYSCTL register, FLAG2 is configured as IRQ2.
When bit 19 is set (=1) in the SYSCTL register, FLAG3 is configured as TIMEXP which
indicates that the system timer has expired.
V
The following symbols appear in the Type column of
A = Asynchronous, G = Ground, I = Input, O = Output,
P = Power Supply, S = Synchronous, (A/D) = Active Drive,
(O/D) = Open Drain, and T = Three-State.
DDEXT
• DAI_Px, SPICLK, MISO, MOSI, EMU, TMS,TRST, TDI
and AD15-0 (NOTE: These pins have internal pull-up
resistors.)
for details of the AD pin operation:
or GND, except for the following:
Table 3 on page 13
for a list of how the AD15-0 pins
Table
Address
2: