SPNA239 September   2019 RM46L440 , RM46L450 , RM46L830 , RM46L840 , RM46L850 , RM46L852 , RM48L530 , RM48L540 , RM48L730 , RM48L740 , RM48L940 , RM48L950 , RM48L952 , RM57L843 , TMS570LC4357 , TMS570LC4357-EP , TMS570LC4357-SEP , TMS570LS0232 , TMS570LS0332 , TMS570LS0432 , TMS570LS10106 , TMS570LS10116 , TMS570LS10206 , TMS570LS1114 , TMS570LS1115 , TMS570LS1224 , TMS570LS1225 , TMS570LS1227 , TMS570LS20206 , TMS570LS20206-EP , TMS570LS20216 , TMS570LS20216-EP , TMS570LS2124 , TMS570LS2125 , TMS570LS2134 , TMS570LS2135 , TMS570LS3134 , TMS570LS3135 , TMS570LS3137 , TMS570LS3137-EP

 

  1.   HALCoGen Ethernet Driver With lwIP Integration Demo and Active Web Server Demo
    1.     Trademarks
    2. 1 Introduction
    3. 2 Supported Features
    4. 3 Get the Software
    5. 4 Configuring EMAC and MDIO Using HALCoGen GUI for the lwIP Demo
      1. 4.1 RM46x, RM48x and TMS570LSx HDK
      2. 4.2 TMS570LC43x and RM57x HDK
      3. 4.3 RM57x Launchpad (LAUNCHXL2 RM57x)
      4. 4.4 TMS570LC43 Launchpad (LAUNCHXL2 570LC43x)
    6. 5 Additional Changes for Active Web Server Demo
      1. 5.1 HALCoGen Configuration Changes
      2. 5.2 lwIP Port Changes
      3. 5.3 CCS Project Structure
      4. 5.4 Changing the Web Pages Rendered by Web Server
    7. 6 Programming Sequence Using HALCoGen Generated Drivers
    8. 7 Design of lwIP Integration
      1. 7.1 Hardware Abstraction Layer
      2. 7.2 lwIP Interface Layer
      3. 7.3 Hercules Development Network Interface Layer
        1. 7.3.1 Network Device Initialization
        2. 7.3.2 Packet Data Transmission
        3. 7.3.3 Packet Data Reception
      4. 7.4 lwIP Application Layer
      5. 7.5 System Application Layer
    9. 8 Release Folder Structure
    10. 9 Run the Test
      1. 9.1 Hardware Setup
      2. 9.2 Building and Executing the lwIP Demo
      3. 9.3 Building and Executing the Active Web Server Demo
        1. 9.3.1 I/O Control Demo 1
        2. 9.3.2 I/O Control Demo 2

7.3.3 Packet Data Reception

Packet reception takes place in the context of the interrupt handler for receive. As described earlier, the receive buffer descriptors are en-queued to the DMA before the reception can actually begin. The pbuf allocated for maximum length, may actually contain a chain of packet buffers. The descriptors are updated for OWNER flag only. The EOP, SOP and EOQ are updated by the DMA upon completion of the reception. One important point to note is that, the actual data received may be less/more than the max length allocated. Hence, the pbuf chain needs to be adjusted as detailed here. First, the active_head (which is the first BD en-queued) is checked for OWNER bit having been cleared by the DMA. Then, the BD list is traversed, starting at the active_head, to find the EOP BD, which is the last BD of the current packet. While doing so, if the EOP is not found on the current BD, then the pbuf of the current BD is chained to the pbuf of the next BD, since the current packet has spilled over to the next BD. Once, the EOP is found the last pbuf is updated as the terminator (pbuf->next = NULL). Thus, the entire packet is collected and passed to the upper layer for processing. Since, the current BD has been done with, it is put back at the free_head, by allocating a new pbuf.