Embedded Peripherals IP User Guide

ID 683130
Date 10/18/2021
Public

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Document Table of Contents
1. Introduction 2. Avalon® -ST Multi-Channel Shared Memory FIFO Core 3. Avalon® -ST Single-Clock and Dual-Clock FIFO Cores 4. Avalon® -ST Serial Peripheral Interface Core 5. SPI Core 6. SPI Agent/JTAG to Avalon® Host Bridge Cores 7. Intel eSPI Agent Core 8. eSPI to LPC Bridge Core 9. Ethernet MDIO Core 10. Intel FPGA 16550 Compatible UART Core 11. UART Core 12. JTAG UART Core 13. Intel FPGA Avalon® Mailbox Core 14. Intel FPGA Avalon® Mutex Core 15. Intel FPGA Avalon® I2C (Host) Core 16. Intel FPGA I2C Agent to Avalon® -MM Host Bridge Core 17. Intel FPGA Avalon® Compact Flash Core 18. EPCS/EPCQA Serial Flash Controller Core 19. Intel FPGA Serial Flash Controller Core 20. Intel FPGA Serial Flash Controller II Core 21. Intel FPGA Generic QUAD SPI Controller Core 22. Intel FPGA Generic QUAD SPI Controller II Core 23. Interval Timer Core 24. Intel FPGA Avalon FIFO Memory Core 25. On-Chip Memory (RAM and ROM) Core 26. On-Chip Memory II (RAM or ROM) 27. Optrex 16207 LCD Controller Core 28. PIO Core 29. PLL Cores 30. DMA Controller Core 31. Modular Scatter-Gather DMA Core 32. Scatter-Gather DMA Controller Core 33. SDRAM Controller Core 34. Tri-State SDRAM Core 35. Video Sync Generator and Pixel Converter Cores 36. Intel FPGA Interrupt Latency Counter Core 37. Performance Counter Unit Core 38. Vectored Interrupt Controller Core 39. Avalon® -ST Data Pattern Generator and Checker Cores 40. Avalon® -ST Test Pattern Generator and Checker Cores 41. System ID Peripheral Core 42. Avalon® Packets to Transactions Converter Core 43. Avalon® -ST Multiplexer and Demultiplexer Cores 44. Avalon® -ST Bytes to Packets and Packets to Bytes Converter Cores 45. Avalon® -ST Delay Core 46. Avalon® -ST Round Robin Scheduler Core 47. Avalon® -ST Splitter Core 48. Avalon® -MM DDR Memory Half Rate Bridge Core 49. Intel FPGA GMII to RGMII Converter Core 50. Intel FPGA MII to RMII Converter Core 51. Intel FPGA HPS GMII to TSE 1000BASE-X/SGMII PCS Bridge Core 52. Intel FPGA HPS EMAC to Multi-rate PHY GMII Adapter Core 53. Intel FPGA MSI to GIC Generator Core

10.4.1. rbr_thr_dll

Identifier Title Offset Access Reset Value Description
rbr_thr_dll Rx Buffer, Tx Holding, and Divisor Latch Low 0x0 RW 0x0000000 This is a multi-function register. This register holds receives and transmit data and controls the least-signficant 8 bits of the baud rate divisor.
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
-
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- rbr_thr_dll
Table 75.  rbr_thr_dll Fields
Bit Name/Identifier Description Access Reset
[31:8] - Reserved R 0x0
[7:0] rbr_thr_dll
  • Receive Buffer Register:

    This register contains the data byte received on the serial input port (sin). The data in this register is valid only if the Data Ready (LSR[0] is set to 1). If FIFOs are disabled (FCR[0] is cleared to 0) the data in the RBR must be read before the next data arrives, otherwise it will be overwritten, resulting in an overrun error. If FIFOs are enabled (FCR[0] set to 1) this register accesses the head of the receive FIFO. If the receive FIFO is full, and this register is not read before the next data character arrives, then the data already in the FIFO will be preserved but any incoming data will be lost. An overrun error will also occur.

  • Transmit Holding Register:

    This register contains data to be transmitted on the serial output port (sout). Data should only be written to the THR when the THR Empty bit (LSR[5] is set to 1). If FIFOs are disabled (FCR[0] is set to 0) and THRE is set to 1, writing a single character to the THR clears the THRE. Any additional writes to the THR before the THRE is set again causes the THR data to be overwritten. If FIFO's are enabled (FCR[0] is set to 1) and THRE is set, the FIFO can be filled up to a pre-configured depth (FIFO_DEPTH). Any attempt to write data when the FIFO is full results in the write data being lost.

  • Divisor Latch Low:

    This register makes up the lower 8-bits of a 16-bit, Read/write, Divisor Latch register that contains the baud rate divisor for the UART. This register may only be accessed when the DLAB bit (LCR[7] is set to 1). The output baud rate is equal to the system clock (clk) frequency divided by sixteen times the value of the baud rate divisor, as follows:

    baud rate = (system clock freq) / (16 * divisor)

    Note: With the Divisor Latch Registers (DLL and DLH) set to zero, the baud clock is disabled and no serial communications will occur. Also, once the DLL is set, at least 8 system clock cycles should be allowed to pass before transmitting or receiving data.
RW 0x00