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Advanced Technology Attachment (ATA)
23-10
Freescale Semiconductor
•
DMA request. Bit 7 of the interrupt registers control ATA DMA request. If the DMA bit is set in
the ATA_IER and ATA_ISR registers, a request is sent to the DMA controller. The goal of this
request is to inform the DMA that running data transfer has ended.
These three interrupt registers have mostly the same bits. If a bit is set in the ATA_ISR register, its interrupt
is pending and produces an interrupt if the corresponding bit is set in the ATA_IER register. Some bits in
the ATA_ISR are sticky bits. Writing a 1 to the corresponding bit in the interrupt clear register (ATA_ICR)
resets them.
23.3.6.1
Interrupt Status Register (ATA_ISR)
The interrupt status register reports the status of various conditions of the ATA controller and its FIFO.
Address: 0x9000_0028 (ATA_ISR)
Access: User read-only
7
6
5
4
3
2
1
0
R
DMA
FUF
FOF
IDLE
INT
W
Reset
0
0
0
1
0
—
—
—
1
Bits DMA and INT only reset to 0 if during reset the interrupt input is low.
Figure 23-7. Interrupt Status Register (ATA_ISR)
Table 23-5. ATA_ISR Field Descriptions
Field
Description
7
DMA
ATA DMA request. Reflects the value of the ATA_INTRQ interrupt input signal. When this bit is set in the
ATA_ISR and ATA_IER registers, the DMA end-of-transfer request is sent. The interrupt clear register, ATA_ICR,
has no influence on this bit.
0 ATA_INTRQ negated
1 ATA_INTRQ asserted
6
FUF
FIFO underfow. Sticky bit that reports FIFO underflow. It is cleared by writing a 1 to this bit in the ATA_ICR
register. When this bit is set in the ATA_ISR and ATA_IER registers, an interrupt is requested to the CPU.
0 No FIFO underflow
1 FIFO underflow detected
5
FOF
FIFO overflow. Sticky bit that reports FIFO overflow. It is cleared by writing a 1 to this bit in the ATA_ICR register.
When this bit is set in the ATA_ISR and ATA_IER registers, an interrupt is requested to the CPU.
0 No FIFO overflow
1 FIFO overflow detected
4
IDLE
Controller idle. Indicates the ATA protocol engine is idle (there is no activity on the ATA bus). When the bit is set
in the ATA_ISR and ATA_IER registers, an interrupt is requested to the CPU. The ATA_ICR register has no
influence on this bit.
0 Activity on the ATA bus
1 No activity on the ATA bus, engine is idle
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...