82091AA Datasheet, PDF (25/204 Pages) Intel Corporation – ADVANCED INTEGRATED PERIPHERAL (AIP)

82091AA
82091AA
Signal
Name
STROBE
BUSY
ACK
SELECT
PERROR
FAULT
INIT
AUTOFD
PD 7 0
SELECTIN
Type
ECP Protocol Signal Name and Description
O HOST CLOCK (HostClk) In the forward direction the 82091AA asserts
STROBE (HostClk) to instruct the peripheral to latch the data on PD 7 0
During write operations the peripheral should latch data on the rising edge of
STROBE (HostClk) STROBE (HostClk) handshakes with BUSY (PeriphAck)
during write operations and is negated after the 82091AA detects BUSY
(PeriphAck) asserted STROBE (HostClk) is not asserted by the 82091AA again
until BUSY (PeriphAck) is detected negated For read operations (reverse
direction) STROBE (HostClk) is not used
I
PERIPHERAL ACKNOWLEDGE (PeriphAck) The peripheral device asserts this
signal during a host write operation to acknowledge receipt of data The
peripheral device then negates the signal after STROBE is detected high to
terminate the transfer For host write operations (forward direction) this signal
handshakes with STROBE (HostClk) During a host read operation (reverse
direction) BUSY (PeriphAck) is normally low and is driven high by the peripheral
to identify Run Length Encoded (RLE) data
I
PERIPHERAL CLOCK (PeriphClk) During a peripheral to host transfer (reverse
direction) ACK (PeriphClk) is asserted by the peripheral to indicate data is valid
on the data bus and then negated after AUTOFD is detected high This signal
handshakes with AUTOFD to transfer data
I
XFLAG (Xflag) This signal is asserted by the peripheral to indicate that it is on-
line The status of this signal line is reported in the PSTAT Register
I
ACKNOWLEDGE REVERSE (AckReverse ) PERROR (AckReverse ) is
driven low by the peripheral to acknowledge a reverse transfer request by the
host This signal handshakes with INIT (ReverseRequest ) The status of this
signal line is reported in the PSTAT Register
I
PERIPHERAL REQUEST (PeriphRequest ) The peripheral asserts FAULT
(PeriphRequest ) to request a reverse transfer The status of this signal line is
reported in the PSTAT Register
O REVERSE REQUEST (ReverseRequest ) The host controls this signal via the
PCON Register to indicate the transfer direction The host asserts this signal to
request a reverse transfer direction and negates the signal for a forward transfer
direction
O HOST ACKNOWLEDGE (HostAck) The 82091AA asserts AUTOFD
(HostAck) to request data from the peripheral (reverse direction) This signal
handshakes with ACK (PeriphClk) AUTOFD (HostAck) is negated when the
peripheral indicates valid state of the data bus (i e ACK is detected asserted)
In the forward direction AUTOFD (HostAck) indicates whether PD 7 0 contain
an address RLE or data The 82091AA asserts this signal to identify an address
RLE transfer and negates it to identify a data transfer
I O DATA PD 7 0 is a bi-directional data bus that transfers data addresses or RLE
data
O ECP MODE (ECPmode) The host (via the PCON Register) negates this signal
during ECP mode operation
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