62.128 GMAC Credit-Based Shaping IdleSlope Register for Queue B

Credit-based shaping must be disabled in GMAC_CBSCR before updating this register.

Name: GMAC_CBSISQB
Offset: 0x4C4
Reset: 0x00000000
Property: Read/Write

Bit 3130292827262524 
 IS[31:24] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 2322212019181716 
 IS[23:16] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 15141312111098 
 IS[15:8] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 76543210 
 IS[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 31:0 – IS[31:0] IdleSlope

IdleSlope value for queue B in bytes/second.

The IdleSlope value is defined as the rate of change of credit when a packet is waiting to be sent. This must not exceed the port transmit rate which is dependent on the speed of operation, e.g., 100 Mb/second = 0x017D7840.

If 50% of bandwidth was to be allocated to a particular queue in 100 Mb/second mode, then the IdleSlope value for that queue would be calculated as 0x017D7840/2.