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I
2
C controller contains a software programmable register,
IC_SDA_HOLD
, to enable dynamic adjustment
of the SDA hold time. †
DMA Controller Interface
The I
2
C controller supports DMA signaling to indicate when data is ready to be read or when the transmit
FIFO needs data. This support requires 2 DMA channels, one for transmit data and one for receive data.
The I
2
C controller supports both single and burst DMA transfers. System software can choose the DMA
burst mode by programming an appropriate value into the threshold registers. The recommended setting
of the FIFO threshold register value is half full.
To enable the DMA controller interface on the I
2
C controller, you must write to the DMA control register
(DMACR) bits. Writing a 1 into the TDMAE bit field of DMACR register enables the I
2
C controller transmit
handshaking interface. Writing a 1 into the RDMAE bit field of the DMACR register enables the I
2
C controller
receive handshaking interface. †
Related Information
on page 16-1
For details about the DMA burst length microcode setup, refer to the
DMA controller
chapter of the
Cyclone
V Device Handbook, Volume 3
.
Clocks
Each I
2
C controller is connected to the
l4_sp_clk
clock, which clocks transfers in standard and fast mode.
The clock input is driven by the clock manager.
Related Information
on page 2-1
For more information, refer to
Clock Manager
.
Resets
Each I
2
C controller has a separate reset signal. The reset manager drives the signals on a cold or warm reset.
Related Information
on page 3-1
For more information, refer to
Reset Manager
.
Interface Pins
All instances of the I
2
C controller connect to external pins through pin multiplexers. Pin multiplexing allows
all instances to function simultaneously and independently. The pins must be connected to a pull-up resistors
and the I
2
C bus capacitance cannot exceed 400 pF.
Table 20-3: I
2
C Controller Interface Pins
Description
Direction
Signal Width
Pin Name
Serial clock
Bidirectional
1 bit
SCL
Serial data
Bidirectional
1 bit
SDA
I2C Controller
Altera Corporation
cv_54020
DMA Controller Interface
20-12
2013.12.30