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GR716-DS-UM, May 2019, Version 1.29
96
www.cobham.com/gaisler
GR716
9: 8
SpaceWire Reference Clock (SEL) - Select SpaceWire reference clock
0x0 - Bypass when PLL is in power down mode (Clock source from external signal SYS_CLK or SPW_CLK)
0x1 - Clock generated from PLL
All other values will result in the clock generated from the PLL to be used.
The output from the PLL is always 400 MHz
* This registers default value can be changed after reset due to bootstrap pins
7: 0
SpaceWire Reference Clock Divisor (DIV) - Set the divisor for input reference clock. Zero (default) bypass the
divisor.
When bitfield DUTY period is set to 0x0 or 0x1. The input clock frequency will be divided by 2xDIV clock
cycles with the duty cycle set to 50%. Valid configurations when DUTY period is set to 0 or 1:
0x00 - Bypass i.e. input frequency is divided by 1
0x02 - Divide input frequency by 4
0x04 - Divide input frequency by 8
0x06 - Divide input frequency by 12
0x08 - Divide input frequency by 16
0x0A - Divide input frequency by 20
0x0C - Divide input frequency by 24
0x0E - Divide input frequency by 28
0x10 - Divide input frequency by 32
0x14 - Divide input frequency by 40
0x16 - Divide input frequency by 44
0x18 - Divide input frequency by 48
0x1A - Divide input frequency by 52
0x1C - Divide input frequency by 56
0x1E - Divide input frequency by 60
All other combinations is not valid.
When bitfield DUTY period is equal or greater then 0x2.The DIV bifield will divide the input frequency by DIV
clock cycles and with the duty cycle defined in the DUTY bitfield.
0x04 - Divide input frequency by 4
0x06 - Divide input frequency by 6
0x08 - Divide input frequency by 8
0x0A - Divide input frequency by 10
0x0C - Divide input frequency by 12
0x0E - Divide input frequency by 14
0x10 - Divide input frequency by 16
0x14 - Divide input frequency by 20
0x16 - Divide input frequency by 22
0x18 - Divide input frequency by 24
0x1A - Divide input frequency by 26
0x1C - Divide input frequency by 28
0x1E - Divide input frequency by 30
All other combinations is not valid
Table 83.
0x10 - MILREF - Select reference for 1553B clock
31
24 23
16 15
10
9
8
7
0
RESERVED
DUTY
RESERVED
SEL
DIV
0x0
0x0
0x0
0
0
r
rw
r
rw
rw
31: 24
RESERVED
23: 16
DUTY cycle for generated clock frequency - The duty cycle bitfield specifies how many of the total clock cycles
specified in the DIV bitfield the generated clock shall be high. IF this register is set to 0x0 the duty cycle will be
set to clock cycles defined in DIV and the clock period to 2xDIV.
Table 82.
0x0C - SPWREF - Select reference for SpaceWire clock