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GR716-DS-UM, May 2019, Version 1.29
376
www.cobham.com/gaisler
GR716
37
I
2
C to AHB bridge
The GR716 microcontroller comprises an I2C to AHB bridge (I2C2AHB). The I2C to AHB bridge
controls its own external pins and has a unique AMBA address described in chapter 2.11. The I2C to
AHB bridge is connected to external pins via the IOMUX.
The control and status registers are located on APB bus in the address range from 0x80105000 to
0x80105FFF. See I2C to AHB bridge connections in the next drawing. The figure shows memory
locations and functions used for I2C2AHB configuration and control.
The primary clock gating unit
GRCLKGATE
described in section 26 is used to enable/disable the
I2C to AHB bridge. The unit
GRCLKGATE
can also be used to perform reset of the I2C to AHB
bridge. Software must enable clock and release reset described in section 26 before configuration and
transmission can start.
External IO selection and configuration is made in the system IO configuration registers (
GRG-
PREG
) in the address range from 0x8000D000 to 0x8000D03F. See section 7.1 for further informa-
tion.
The system can be configured to protect and restrict access to the I2C to AHB bridge in the
MEM-
PROT
unit. See section 47 for more information.
37.1
Overview
The I
2
C slave to AHB bridge is an I
2
C slave that provides a link between the I
2
C bus and AMBA
AHB. The core is compatible with the Philips I
2
C standard and external pull-up resistors must be sup-
plied for both bus lines.
On the I
2
C bus the slave acts as an I
2
C memory device where accesses to the slave are translated to
AMBA accesses. The core can translate I
2
C accesses to AMBA byte, halfword or word accesses. The
core makes use of I
2
C clock stretching but can also be configured to use a special mode without clock
Figure 56.
GR716 I2C2AHB bus and pin connection
GPIO0
LEON3FT
Processor
APB
(0x80000000-
0x800FFFFF)
IOMUX
GPIO63
Main AHB
(0x00000000-
0xFFFFFFFF)
Select Outputs
Enable I2C2AHB clock
(0x8000D000 -
0x8000D03F)
(0x80006000 -
0x8000600F)
GRGPREG
MEMPROT
Memory Protection
(0x8001A000 -
0x8001AFFF)
Bridge
Bridge
GRCLKGATE
Bridge
I2C2AHB
DMA
AHB
Bridge