cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 120

• Manufacturer Part Number: cx28560
• Description: Hdlc Controller
• Manufacturer: Mindspeed Technologies

The CX28560 Memory Organization
5.7.5
Table 5-28. RBUFFC Flexiframe Memory
5.7.6
Table 5-29. RBUFFC Flexiframe Control Register
5-30
31:11
31:26
23:15
10:0
14:0
Bit
Bit
25
24
RSVD
RCHANNEL
RSVD
RNFFRAMEIEN
RNFFRAME
RSVD
RFFRAMESIZE[14:0]
RFFRAMESIZE[1:0]
Field Name
Field Name
RBUFFC Flexiframe Memory
RBUFFC Flexiframe Control Register
Value
The RBUFFC Flexiframe Memory provides the RBUFFC with the order in which to
service the channels – a timing scheduler. The RBUFFC runs through the Flexiframe
Memory line by line, servicing the channel number as in the Flexiframe memory. The
Flexiframe holds a maximum of 21504 entries and a minimum of 12. The number of
entries contained in the Flexiframe is stored in the Flexiframe Control Register, and
should be an exact multiple of 4. The value 0 in the channel number represents an
empty cycle and will be treated as a NOP by the RBUFFC. Because of the Flexiframe
memory organization in lines of four registers each, access to registers must be in
multiples of four registers.
This register contains the characteristics of the Flexiframe being programmed. When
moving to a new Flexiframe this register is vital for the smooth transition. In order to
swap to a new Flexiframe, the host should write the new Flexiframe to the
then write the Flexiframe Control register with the new frame size, the RNFFRAMEI
interrupt enable set to 1 or 0, and the RNFFRAME field set to 1. The host knows that
the transition to the new Flexiframe has been made either when a NFFRAMEI
interrupt is generated (if the RNFFRAMEIEN was set to 1) or by polling the
RNFFRAME bit for a 0 value. An additional change of Flexiframe before some
acknowledgement has been recorded may produce undefined behavior.
—
0
Value
—
—
Reserved.
Logical Channel Number assigned to slot in Flexiframe.
0
0
1
0
3
Mindspeed Technologies™
Reserved.
Change of Flexiframe Complete Interrupt Disabled.
Change of Flexiframe Complete Interrupt Enabled.
Once the RBUFFC has completed the switch to the new Flexiframe a Change of
Flexiframe Complete interrupt will be generated.
New Flexiframe Indication.
This bit serves as an indication to the RBUFFC to switch to the new Flexiframe.
When the RBUFFC completes the switch to the new Flexiframe, it resets this
indication to 0. It is illegal for the system to set this bit to 0 as this will produce
undefined behavior.
Reserved.
Flexiframe Size.
This field provides the RBUFFC the actual number of entries in the Flexiframe
minus one. Because the number of entries in the Flexiframe must be a multiple of
four, the last two bits of this field will be set to 11b. The value of this field may
range from 11 to 21503 (indicating Flexiframe sizes of 12 to 21504 respectively).
Advance Information
Description
Description
CX28560 Data Sheet
28560-DSH-001-B
Table
5-28,