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public interface MMIODevice
The MMIODevice class provides methods to retrieve memory-mapped registers and memory blocks
of a peripheral device.
MMIODevice instance can be acquired by a call to MMIOManager.getDevice(int)
or MMIOManager.getDevice(java.lang.String).
With memory-mapped I/O, peripheral devices can be controlled by directly reading or writing to
memory areas representing the registers or memory blocks of the peripheral device.
Each register or memory block is represented by a RawMemory instance.
All the mapped registers (including memory blocks) of an MMIO device may be retrieved by a call to
#getRegisters(). The RawMemory instance associated to a register
has a fixed/determined index in the array returned by #getRegisters().
Each register or memory block is also usually assigned a name which can be used
for name-based lookup.
An application can register an MMIOEventListener instance to monitor
native events of the designated type fired by the peripheral device.
To register a MMIOEventListener instance, the application
must call the setMMIOEventListener()
method.
The registered listener
can later on be removed by calling the same method with a null listener parameter.
Asynchronous notification may not be supported by all memory-mapped devices.
An attempt to set a listener on a memory-mapped device which does not supports it will result in
an InvalidOperationException being thrown.
Typical usage example is as follows:
static final int INTERRUPT = 0;
MMIODevice rtc = MMIOManager.getDevice("RTC"); // HITACHI HD146818 Real Time Clock
//The RTC device has 14 bytes of clock and control registers and 50 bytes
// of general purpose RAM (see the data sheet of the HITACHI HD146818 Real Time Clock).
RawByte seconds = rtc.getByteRegister("Seconds");
RawByte secAlarm = rtc.getByteRegister("SecAlarm");
RawByte minutes = rtc.getByteRegister("Minutes");
RawByte minAlarm = rtc.getByteRegister("MinAlarm");
RawByte hours = rtc.getByteRegister("Hours");
RawByte hrAlarm = rtc.getByteRegister("HrAlarm");
... // More registers
RawByte registerA = rtc.getByteRegister("RegisterA");
RawByte registerB = rtc.getByteRegister("RegisterB");
RawByte registerC = rtc.getByteRegister("RegisterC");
RawByte registerD = rtc.getByteRegister("RegisterD");
RawBlock userRAM = rtc.getBlock("UserRam");
private class AlarmListener implements MMIOEventListener {
public void eventDispatched(MMIOEvent event) {
int i = registerC.get();
// Check the Alarm Interrupt Flag (AF)
if ((registerC.get()&0X20) != 0) {
// Register C is automatically cleared once read
... // Notify application of alarm
}
}
}
// Sets the daily alarm for after some delay
public void setAlarm(byte delaySeconds, byte delayMinutes, byte delayHours) {
//Directly read from/write to the registers using RawByte instances.
byte currentSeconds = seconds.get();
byte currentMinutes = minutes.get();
byte currentHours = hours.get();
int i = (currentSeconds + delaySeconds) % 60;
int j = (currentSeconds + delaySeconds) / 60;
seconds.set(i);
i = (currentMinutes + delayMinutes + j) % 60;
j = (currentMinutes + delayMinutes + j) / 60;
minutes.set(i);
i = (currentHours + delayHours + j) % 24;
hours.set(i);
rtc.setMMIOEventListener(INTERRUPT, new AlarmListener());
// Set the Alarm Interrupt Enabled (AIE) flag
registerB.set((byte) (registerB.get()|0X20));
}
When done, an application should call the MMIODevice.close() method
to release the MMIO device. Any further attempt to access an MMIO device which has been
released will result in a PeripheralNotAvailableException been thrown.
Note that the event types (IDs) supported by a memory-mapped device are device as well as
platform specific. Refer to the device data sheet and the platform configuration.
MMIOManager,
MMIOPermission,
PeripheralNotAvailableException| Field Summary | |
static int |
BIG_ENDIAN
Big-endian byte ordering. |
static int |
LITTLE_ENDIAN
Little-endian byte ordering. |
static int |
MIXED_ENDIAN
Mixed-endian (non-standard) byte ordering. |
| Method Summary | |
RawBlock |
getBlock(java.lang.String name)
Gets the designated memory block. |
int |
getByteOrdering()
Returns the byte ordering of this memory-mapped peripheral device. |
RawByte |
getByteRegister(java.lang.String name)
Gets the designated register holding a byte value. |
RawInt |
getIntRegister(java.lang.String name)
Gets the designated register holding a int value. |
RawLong |
getLongRegister(java.lang.String name)
Gets the designated register holding a long value. |
RawShort |
getShortRegister(java.lang.String name)
Gets the designated register holding a short value. |
void |
setMMIOEventListener(int eventId,
MMIOEventListener listener)
Registers a MMIOEventListener instance to monitor native events of the designated type fired by the peripheral device mapped to this MMIODevice object. |
| Methods inherited from interface com.oracle.deviceaccess.Peripheral |
close, getID, getName |
| Field Detail |
static final int LITTLE_ENDIAN
static final int BIG_ENDIAN
static final int MIXED_ENDIAN
| Method Detail |
RawByte getByteRegister(java.lang.String name)
throws PeripheralNotAvailableException
byte value.
name - name of the register.
RawByte object encapsulating the byte value of the designated register.
java.lang.IllegalArgumentException - if the provided name does not correspond to any register or
if the type of of the value held in the register does not match.
java.lang.NullPointerException - if name is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
RawShort getShortRegister(java.lang.String name)
throws PeripheralNotAvailableException
short value.
name - name of the register.
RawShort object encapsulating the short value of the designated register.
java.lang.IllegalArgumentException - if the provided name does not correspond to any register or
if the type of of the value held in the register does not match.
java.lang.NullPointerException - if name is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
RawInt getIntRegister(java.lang.String name)
throws PeripheralNotAvailableException
int value.
name - name of the register.
RawInt object encapsulating the int value of the designated register.
java.lang.IllegalArgumentException - if the provided name does not correspond to any register or
if the type of of the value held in the register does not match.
java.lang.NullPointerException - if name is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
RawLong getLongRegister(java.lang.String name)
throws PeripheralNotAvailableException
long value.
name - name of the register.
RawLong object encapsulating the long value of the designated register.
java.lang.IllegalArgumentException - if the provided name does not correspond to any register or
if the type of of the value held in the register does not match.
java.lang.NullPointerException - if name is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
RawBlock getBlock(java.lang.String name)
throws PeripheralNotAvailableException
name - name of the memory block.
RawBlock object encapsulating the designated memory block.
java.lang.IllegalArgumentException - if the provided name does not correspond to any memory block or
if the type does not match.
java.lang.NullPointerException - if name is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
void setMMIOEventListener(int eventId,
MMIOEventListener listener)
throws PeripheralNotAvailableException
MMIOEventListener instance to monitor native events of the designated type fired by the peripheral device mapped to this MMIODevice object.
While the listener can be triggered by hardware interrupts,
there are no real-time guarantees of when the listener will be called.
If listener is null then listener previously registered
for the specified event type will be removed.
Only one listener can be registered at a particular time for a particular event type.
eventId - ID of the native event to listen to.listener - the MMIOEventListener instance to be notified upon occurrence of the designated event.
java.lang.IllegalArgumentException - if eventId does not correspond to any supported event.
InvalidOperationException - if this MMIODevice object does not support asynchronous event notification
or if listener is not null and a listener is already registered for the specified event type.
java.lang.NullPointerException - if listener is null.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
int getByteOrdering()
throws PeripheralNotAvailableException
BIG_ENDIAN if big-endian; LITTLE_ENDIAN if little-endian;
MIXED_ENDIAN otherwise.
PeripheralNotAvailableException - if the peripheral is not currently available (has been released).
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