ADM-XRC-9R1 User Manual
V1.7 - 16th Sept 2020
3.4.7.3 RF Clock Programming
The RF reference clocks are programmed from the PL using SPI (LMX2594) or uWire (LMK04208). To minimise
FPGA IO pin usage, a CPLD is used to multiplex a single 4-wire IO interface to the FPGA to each of the 4
devices. There are two control bits to select which clock device is active. Both writing and readback are
supported for all devices.
shows the required chip select value to access each device.
LMK04208
0
CPLD
LMX2594
1
LMX2594
2
LMX2594
3
ADC_CLK_224 (AD5,AD4)
ADC_CLK_225 (AB5, AB4)
ADC_CLK_226 (Y5,Y4)
ADC_CLK_227 (V5, V4)
DAC_CLK_228 (L5,L4)
DAC_CLK_229 (J5, J4)
FPGA
4-Wire
Interface
2-bit
Chip Select
uWire
SPI
SPI
SPI
RF Power
Supply Status
Figure 7 : CPLD Connections
Signal
FPGA Pin IO Standard
Description
CLK
H13
LVCMOS33
4-Wire interface clock
CS_L
G13
LVCMOS33
4-Wire interface chip select
SDI
E14
LVCMOS33
4-Wire interface data to device (from FPGA)
SDO
D14
LVCMOS33
4-Wire interface data from device (to FPGA)
SPI_SEL[0]
J14
LVCMOS33
Chip select bit 0
SPI_SEL[1]
J13
LVCMOS33
Chip select bit 1
PREREG_PGOOD
H15
LVCMOS33
Power good signal from RF power supplies.
LDO_PGOOD
H14
LVCMOS33
Power good signal from RF power supplies.
Table 13 : FPGA 4-Wire Connections
Page 14
Functional Description
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