cn8236 Mindspeed Technologies, cn8236 Datasheet - Page 299

• Manufacturer Part Number: cn8236
• Description: Atm Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

CN8236
ATM ServiceSAR Plus with xBR Traffic Management
12.4.2 UTOPIA Configuration Control
28236-DSH-001-B
Table 12-8. Cell Format, Tagging Enabled, 16 Bit Mode
Most options for the CN8236 UTOPIA interface are configured by control bits in
the Config0 and Config1 registers. However, the selection of UTOPIA Level 1
versus Level 2 and of Master or Slave mode is controlled by the input pins
FRCFG0, FRCFG1, and UTOPIA1. Normally, these inputs are hardwired as
required by the system design.
UTOPIA level 2, connecting it to +3.3V selects UTOPIA Level 1. When selecting
UTOPIA Level 2 be sure to program the UTOPIA_MODE bit to logic high to
enable Cell level handshaking (octet level handshaking is not valid in UTOPIA
Level 2).
defined in
the Config0 register. Setting this bit high selects cell-level handshaking. In this
mode, both the CN8236 and the selected port only begin a transfer when there is
room in the FIFO buffers for an entire cell. When UTOPIA Level 2 mode is
selected, this bit MUST be set to logic high.
receive blocks both use the RxClk input. By setting the MULTI_CLK bit of
Config1 to logic high, the transmit side uses the TxClk input. The UTOPIA
receive block continues to use the RxClk.
UTOPIA bus. By setting the MULTI_PHY bit of Config1 to logic high, up to 8
devices can share the bus.
UTOP16 bit of the Config1 register. Setting this bit high enables a 16-bit data path.
15
UTOPIA Level 1/Level 2: Tying the UTOPIA1 input pin to ground selects
Master/Slave selection: Controlled by hardware inputs FRCFG[1:0] as
Octet or Cell Handshaking: This is controlled by the UTOPIA_MODE bit in
UTOPIA clocks: In the default state after a reset, the UTOPIA transmit and
Multi-port operations: By default, the CN8236 expects a single device on the
UTOPIA data bus width: The width of the UTOPIA data bus is selectable by the
Payload 47
Payload 1
Header 1
Header 3
Tag n-1
Tag 1
HEC
Mindspeed Technologies
Table
12-1.
8
7
Payload 48
Payload 2
Not Used
Header 2
Header 4
Tag n-2
Tag 2
0
™
1
Last word of Cell
st
word of Cell
12.0 ATM UTOPIA Interface
12.4 UTOPIA Level 2 Interface
12-9