DS31256 Maxim Integrated Products, DS31256 Datasheet - Page 134

• Manufacturer Part Number: DS31256
• Description: IC CTRLR HDLC 256-CHANNEL 256BGA
• Manufacturer: Maxim Integrated Products

Specifications of DS31256

• Controller Type: HDLC Controller
• Interface: Serial
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 500mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 256-BGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

10.1.5
Targets can terminate the requested bus transaction before any data is transferred because the target is
busy and temporarily unable to process the transaction. Such a termination is called a target retry and no
data is transferred. A target retry is signaled to the initiator by the assertion of PSTOP and not asserting
PTRDY on the initial data phase
retry when the host is accessing the local bus. This occurs when the local bus is operating in the
arbitration mode. It is busy at the instant the host requests access to the local bus. See Section
more details about the operation of the local bus.
Figure 10-6. PCI Target Retry
10.1.6
A target can prematurely terminate a transaction by asserting PSTOP
current state of the ready signals when PSTOP is asserted, data may or may not be transferred. The target
always deasserts PSTOP when it detects that the initiator has deasserted PFRAME. When the DS31256
is a target, it disconnects with data after the first data phase is complete, if the master attempts a burst
transaction. This is because the device does not support burst transactions when it is a target. When it is
an initiator and experiences a disconnect from the target, it attempts another bus transaction (if it still has
the bus granted) after waiting either one (disconnect without data) or two clock cycles (disconnect with
data).
Figure 10-7. PCI Target Disconnect
PCLK
PFRAME
PSTOP
PDEVSEL
PCLK
PFRAME
PIRDY
PTRDY
PSTOP
PDEVSEL
PCI Target Retry
PCI Target Disconnect
1
1
2
2
(Figure
3
3
10-6). When the DS31256 is a target, it only issues a target
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5
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7
(Figure
8
8
10-7). Depending on the
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11.1
for