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interfaces.md

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Hardware Interfaces

Referring to the Comportable guideline for peripheral device functionality, the module i2c has the following hardware interfaces defined

  • Primary Clock: clk_i
  • Other Clocks: none
  • Bus Device Interfaces (TL-UL): tl
  • Bus Host Interfaces (TL-UL): none

Peripheral Pins for Chip IO

Pin name Direction Description
sda inout Serial input data bit
scl inout Serial input clock bit

Inter-Module Signals

Port Name Package::Struct Type Act Width Description
ram_cfg prim_ram_1p_pkg::ram_1p_cfg uni rcv 1
lsio_trigger logic uni req 1 Self-clearing status trigger for the DMA. Set when RX TX FIFO is past their configured watermark matching watermark interrupt behaviour.
tl tlul_pkg::tl req_rsp rsp 1

Interrupts

Interrupt Name Type Description
fmt_threshold Status host mode interrupt: asserted whilst the FMT FIFO level is below the low threshold. This is a level status interrupt.
rx_threshold Status host mode interrupt: asserted whilst the RX FIFO level is above the high threshold. This is a level status interrupt.
acq_threshold Status target mode interrupt: asserted whilst the ACQ FIFO level is above the high threshold. This is a level status interrupt.
rx_overflow Event host mode interrupt: raised if the RX FIFO has overflowed.
controller_halt Status host mode interrupt: raised if the controller FSM is halted, such as on an unexpected NACK or lost arbitration. Check CONTROLLER_EVENTS for the reason. The interrupt will be released when the bits in CONTROLLER_EVENTS are cleared.
scl_interference Event host mode interrupt: raised if the SCL line drops early (not supported without clock synchronization).
sda_interference Event host mode interrupt: raised if the SDA line goes low when host is trying to assert high
stretch_timeout Event host mode interrupt: raised if target stretches the clock beyond the allowed timeout period
sda_unstable Event host mode interrupt: raised if the target does not assert a constant value of SDA during transmission.
cmd_complete Event host and target mode interrupt. In host mode, raised if the host issues a repeated START or terminates the transaction by issuing STOP. In target mode, raised if the external host issues a STOP or repeated START.
tx_stretch Status target mode interrupt: raised if the target is stretching clocks for a read command. This is a level status interrupt.
tx_threshold Status target mode interrupt: asserted whilst the TX FIFO level is below the low threshold. This is a level status interrupt.
acq_stretch Status target mode interrupt: raised if the target is stretching clocks due to full ACQ FIFO or zero count in TARGET_ACK_CTRL.NBYTES (if enabled). This is a level status interrupt.
unexp_stop Event target mode interrupt: raised if STOP is received without a preceding NACK during an external host read.
host_timeout Event target mode interrupt: raised if the host stops sending the clock during an ongoing transaction.

Security Alerts

Alert Name Description
fatal_fault This fatal alert is triggered when a fatal TL-UL bus integrity fault is detected.

Security Countermeasures

Countermeasure ID Description
I2C.BUS.INTEGRITY End-to-end bus integrity scheme.