Visible to Intel only — GUID: lxg1520633295594
Ixiasoft
Visible to Intel only — GUID: lxg1520633295594
Ixiasoft
3.2.1.1.2. Read Data Mover Avalon-ST Descriptor Sinks
Signal Name | Direction | Description |
---|---|---|
rddm_desc_ready_o | Output | When asserted, this ready signal indicates the normal descriptor queue in the Read Data Mover is ready to accept data. The ready latency of this interface is 3 cycles. |
rddm_desc_valid_i | Input | When asserted, this signal qualifies valid data on any cycle where data is being transferred to the normal descriptor queue. On each cycle where this signal is active, the queue samples the data. |
rddm_desc_data_i[159:0] | Input | [159:152] : descriptor ID [151:149] : application specific [148] : single destination [147] : reserved [146] : reserved [145:128] : number of dwords to transfer up to 1 MB [127:64] : destination Avalon® -MM address [63:0] : source PCIe address |
When the single destination bit is set, the transfers use the same destination address. If the bit is not set, the address increments for each transfer.
Signal Name | Direction | Description |
---|---|---|
rddm_prio_ready_o | Output | When asserted, this ready signal indicates the priority descriptor queue in the Read Data Mover is ready to accept data.This ready latency of this interface is 3 cycles. |
rddm_prio_valid_i | Input | When asserted, this signal qualifies valid data on any cycle where data is being transferred to the priority descriptor queue. On each cycle where this signal is active, the queue samples the data. |
rddm_prio_data_i[159:0] | Input | [159:152] : descriptor ID [151:149] : application specific [148] : single destination [147] : reserved [146] : reserved [145:128] : number of dwords to transfer up to 1 MB [127:64] : destination Avalon® -MM address [63:0] : source PCIe address |
The Read Data Mover internally keeps two queues of descriptors. The priority queue has absolute priority over the normal queue. Use it carefully to avoid starving the normal queue.
If the Read Data Mover receives a descriptor on the priority interface while processing a descriptor from the normal queue, it switches to processing descriptors from the priority queue as soon as it has completed the current descriptor. The Read Data Mover resumes processing the descriptors from the normal queue once the priority queue is empty. Do not use the same descriptor ID simultaneously in the two queues as there would be no way to distinguish them on the Status Avalon-ST source interface.