EP7311 Datasheet, PDF (6/54 Pages) Cirrus Logic – HIGH-PERFORMANCE, LOW-POWER SYSTEM-ON-CHIP WITH SDRAM AND ENHANCED DIGITAL AUDIO INTERFACE

EP7311
High-Performance, Low-Power System on Chip
64-Keypad Interface
Matrix keyboards and keypads can be easily read by the
EP7311. A dedicated 8-bit column driver output
generates strobes for each keyboard column signal. The
pins of Port A, when configured as inputs, can be
selectively OR'ed together to provide a keyboard
interrupt that is capable of waking the system from a
STANDBY or IDLE state.
• Column outputs can be individually set high with the
remaining bits left at high-impedance
• Column outputs can be driven all-low, all-high, or all-
high-impedance
• Keyboard interrupt driven by OR'ing together all Port
A bits
• Keyboard interrupt can be used to wake up the
system
• 8×8 keyboard matrix usable with no external logic,
extra keys can be added with minimal glue logic
.
Pin Mnemonic
I/O
Pin Description
nEINT[2:1]
EINT[3]
nEXTFIQ
nMEDCHG/nBROM
(Note)
I External interrupt
I External interrupt
I External Fast Interrupt input
I Media change interrupt input
Table K. Interrupt Controller Pin Assignments
Note: Pins are multiplexed. See Table S on page 8 for more
information.
Real-Time Clock
The EP7311 contains a 32-bit Real Time Clock (RTC) that
can be written to and read from in the same manner as
the timer counters. It also contains a 32-bit output match
register which can be programmed to generate an
interrupt.
• Driven by an external 32.768 kHz crystal oscillator
Pin Mnemonic
I/O
Pin Description
COL[7:0]
O
Keyboard scanner column drive
Table J. Keypad Interface Pin Assignments
Interrupt Controller
When unexpected events arise during the execution of a
program (i.e., interrupt or memory fault) an exception is
usually generated. When these exceptions occur at the
same time, a fixed priority system determines the order
in which they are handled. The EP7311 interrupt
controller has two interrupt types: interrupt request
(IRQ) and fast interrupt request (FIQ). The interrupt
controller has the ability to control interrupts from 22
different FIQ and IRQ sources.
• Supports 22 interrupts from a variety of sources (such
as UARTs, SSI1, and key matrix.)
• Routes interrupt sources to the ARM720T’s IRQ or
FIQ (Fast IRQ) inputs
• Five dedicated off-chip interrupt lines operate as level
sensitive interrupts
Pin Mnemonic
Pin Description
RTCIN
RTCOUT
VDDRTC
VSSRTC
Real-Time Clock Oscillator Input
Real-Time Clock Oscillator Output
Real-Time Clock Oscillator Power
Real-Time Clock Oscillator Ground
Table L. Real-Time Clock Pin Assignments
PLL and Clocking
• Processor and Peripheral Clocks operate from a single
3.6864 MHz crystal or external 13 MHz clock
• Programmable clock speeds allow the peripheral bus
to run at 18 MHz when the processor is set to 18 MHz
and at 36 MHz when the processor is set to 36, 49 or
74 MHz
Pin Mnemonic
Pin Description
MOSCIN
MOSCOUT
VDDOSC
VSSOSC
Main Oscillator Input
Main Oscillator Output
Main Oscillator Power
Main Oscillator Ground
Table M. PLL and Clocking Pin Assignments
6
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(All Rights Reserved)
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