GR740-UM-DS, Nov 2017, Version 1.7
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GR740
30
Register Bank For I/O and PLL configuration registers
30.1
Overview
The core provides an array of programmable registers that are used to control pin sharing and allows
controlling the PLL reconfiguration unit.
30.2
Operation
30.2.1 Pin multiplexing control
The core controls the pin multiplexing for the PROM/IO interface shared pins.The pins are controlled
by a combination of two register bits according to table 451 below. The pin corresponding to each reg-
ister bit position is described in section 3.3.1.
30.2.2 LVDS pad enable control
The LVDS enable control registers allow to turn off unused LVDS output drivers for the spacewire
links, as well as the differential memory clock output, in order to reduce power consumption. The sin-
gle-ended memory clock output can also be disabled using this register, in case the differential one is
only used. All pads are reset to an enabled state.
30.2.3 Pad drive strength control
Register bits allow adjusting the drive strength of the non-differential pads in the design. The pads
have been divided by function into 20 groups, as shown in table below.
Table 451.
Mapping between register bit and pin function
FTMEN ALTEN Pin function
1
*
PROM/IO interface
0
1
Alternate I/O interface
0
0
GPIO2