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Zilog Z08470 User Manual

Page 134

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UM008101-0601

Direct Memory Access

Bit 0

Indicates whether the DMA has requested the bus after the fast

LOAD command. 1 indicates yes, 0 indicates no.

Bit 1

Indicates whether the DMA’s RDY pin currently has a signal input

that is defined as active by bit 3 of WR5. 1 indicates an active Ready line. 0
indicates an inactive Ready line.

Bit 2

Undefined.

Bit 3

Indicates the state of the Interrupt Pending (IP) latch. A 0 indicates

that an interrupt is pending (the DMA has its INT line active if the interrupt
has not been acknowledged). A 1 indicates no interrupt pending.

Bit 4

A 0 indicates that a match has been found after the last RESET or

REINITIALIZE STATUS BYTE command. A1 indicates no match was
found. See Table 11 to determine where the match occurred.

Bit 5

A 0 indicates that an end-of-block was reached after the last

RESET, LOAD, CONTINUE, or REINITIALIZE STATUS BYTE
command. A 1 indicates no end-of-block was reached. See Table 12 to
determine the contents of counters when the DMA stops.

Bit 6

Undefined.

Bit 7

Undefined.

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