Embedded Peripherals IP User Guide

ID 683130
Date 10/24/2025
Public
Document Table of Contents
1. Introduction 2. Avalon® -ST Serial Peripheral Interface Core 3. SPI Core 4. SPI Agent/JTAG to Avalon® Host Bridge Cores 5. Intel eSPI Agent Core 6. eSPI to LPC Bridge Core 7. Ethernet MDIO Core 8. Intel FPGA 16550 Compatible UART Core 9. UART Core 10. Lightweight UART Core 11. JTAG UART Core 12. Intel FPGA Avalon® Mailbox Core 13. Intel FPGA Avalon® Mutex Core 14. Intel FPGA Avalon® I2C (Host) Core 15. Intel FPGA I2C Agent to Avalon® -MM Host Bridge Core 16. EPCS/EPCQA Serial Flash Controller Core 17. Intel FPGA Serial Flash Controller Core 18. Intel FPGA Serial Flash Controller II Core 19. Intel FPGA Generic QUAD SPI Controller Core 20. Intel FPGA Generic QUAD SPI Controller II Core 21. Interval Timer Core 22. Intel FPGA Avalon FIFO Memory Core 23. On-Chip Memory (RAM and ROM) Intel FPGA IP 24. On-Chip Memory II (RAM or ROM) Intel FPGA IP 25. PIO Core 26. PLL Cores 27. DMA Controller Core 28. Modular Scatter-Gather DMA Core 29. Scatter-Gather DMA Controller Core 30. Video Sync Generator and Pixel Converter Cores 31. Intel FPGA Interrupt Latency Counter Core 32. Performance Counter Unit Core 33. Vectored Interrupt Controller Core 34. System ID Peripheral Core 35. Intel FPGA GMII to RGMII Converter Core 36. HPS GMII to RGMII Adapter IP 37. Intel FPGA MII to RMII Converter Core 38. HPS GMII to TSE 1000BASE-X/SGMII PCS Bridge Core IP 39. Intel FPGA HPS EMAC to Multi-rate PHY GMII Adapter Core 40. Intel FPGA MSI to GIC Generator Core 41. Cache Coherency Translator IP 42. Altera ACE5-Lite Cache Coherency Translator

8.4.6. mcr

Identifier Title Offset Access Reset Value Description
mcr Modem Control Register 0x10 RW 0x00000000 Reports various operations of the modem signals.
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
afce loopback out2 out1 rts dtr
Table 73.  mcr Fields Descriptions
Bit Name/Identifier Description Access Reset
[31:6] Reserved R 0x0
[5] Hardware Auto Flow Control Enable ( afce)

When FIFOs are enabled (FCR[0]), the Auto Flow Control enable bits are active. This enabled UART to dynamically assert and deassert rts_n based on Receive FIFO trigger level

RW 0x0
[4] LoopBack Bit (loopback)

This is used to put the UART into a diagnostic mode for test purposes. If UART mode is NOT active, bit [6] of the modem control register MCR is set to zero, data on the sout line is held high, while serial data output is looped back to the sin line, internally. In this mode all the interrupts are fully functional. Also, in loopback mode, the modem control inputs (dsr_n, cts_n, ri_n, dcd_n) are disconnected and the modem control outputs (dtr_n, rts_n, out1_n, out2_n) are looped-back to the inputs, internally.

RW 0x0
[3] Out2 (out2)

This is used to directly control the user-designated out2_n output. The value written to this location is inverted and driven out on out2_n

RW 0x0
[2] Out1 (out1)

This is used to directly control the user-designated out1_n output. The value written to this location is inverted and driven out on out1_n pin.

RW 0x0
[1] Request to Send (rts)

This is used to directly control the Request to Send (rts_n) output. The Request to Send (rts_n) output is used to inform the modem or data set that the UART is ready to exchange data. When Auto RTS Flow Control is not enabled (MCR[5] set to zero), the rts_n signal is set low by programming this register to a high. If Auto Flow Control is active (MCR[5] set to 1) and FIFO's enable (FCR[0] set to 1), the rts_n output is controlled in the same way, but is also gated with the receiver FIFO threshold trigger (rts_n is inactive high when above the threshold). The rts_n signal will be de-asserted when this register is set low.

RW 0x0
[0] Data Terminal Ready (dtr)

This is used to directly control the Data Terminal Ready output. The value written to this location is inverted and driven out on uart_dtr_n. The Data Terminal Ready output is used to inform the modem or data set that the UART is ready to establish communications.

RW 0x0