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Aeroflex Microelectronics Solutions - HiRel

36-00-00-001

Ver. 1.5.0

4.1.4 Boot Strap Programming on GPIO

Data on pins GPIO[2:0], GAPIO[7:4] and GPIO[15:12] are latched on the rising edge of reset. The states of GPIO[2:0] determine

the data width of the PROM area, and enable EDAC for the PROM area. Chapter 3 of the User’s Manual describes the value of

these inputs to achieve the required operation. The states of GPIO[7:4] provides a means to configure the SpaceWire clock divisor

link bits in the Clock Divisor Register. The states of GPIO[15:12] set the least significant address nibble of the IP and MAC address

for the Ethernet Debug Communication Link (EDCL).

In order for the state of GPIO[2:0] to be properly latched, Aeroflex recommends placing pull-up or pull-down resistors on these pins

to ensure that the setup and hold timing is met. The states of these pins should be statically set prior to the rising edge of RESET.