Z8932120FSC ZILOG [Zilog, Inc.], Z8932120FSC Datasheet - Page 23

• Manufacturer Part Number: Z8932120FSC
• Description: 16-BIT DIGITAL SIGNAL PROCESSORS
• Manufacturer: ZILOG [Zilog, Inc.]

Zilog
PERIPHERAL OPERATION
Disabling Peripherals
Disabling a peripheral (CODEC Interface, Counter) allows
general-purpose use of the EXT address for the disabled
peripheral. If the peripheral is not disabled, the EXT control
signals and EXT data are still provided, but transfer of data
on the EXT pins is not available (because internal transfers
are being processed on the internal bus). Care must be
taken to ensure that control of the EXT bus does not cause
bus conflicts.
Reading Data from CODEC Interface*
External data is serially transferred into the CODEC inter-
face registers from an external CODEC. This serial data is
loaded into EXT5-2 (8- or 16-bit modes). Because the in-
terface is double-buffered, data must be transferred to
LOADING EXT7
Because EXT7 is double-buffered, a pair of writes are per-
formed when loading the EXT7 registers (Figure 19).
LD EXT7, #%54F4
LD EXT7, #%6CDA
LD @P0:0, EXT7
DS97DSP0100
Loads CODEC Timer Register
Reads EXT7-1 and places
data in RAM
Loads Wait-State Register
EXT7-1
Figure 19. EXT7 Register ConÞguration
16
EXT7-1
EXT7-2
P R E L I M I N A R Y
Internal 16-Bit Bus
CODEC Timer Register
Wait-State Register
EXT5-1 before being transferred along the internal data
bus of the processor. This is accomplished by writing data
to EXT5-2.
Writing Data to CODEC Interface
Internal data is transferred from the internal data bus of the
processor to the EXT5-2 register. The CODEC interface
constantly transfers and receives data during normal oper-
ation. Data to be transferred is loaded to EXT5-2 and is au-
tomatically serially transferred.
Note: EXT5-1 and EXT5-2 are used in the example, but
this information applies equally to EXT6-1 and EXT6-2.
(Refer to Figure 20, CODEC Block Diagram.)
Interrupts
The Z89321 features three interrupts:
If all peripherals are enabled, INT0 (general-purpose) can
be used.
INT0
INT1
INT2
EXT7-2
16
16-Bit Digital Signal Processors
General-Purpose
CODEC Interface
13-Bit Timer
Z89321/371/391
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