Other Parts Discussed in Thread: LMX1204
Hi Team,
I'm using the LMX1204EVM in order to evaluate the possibility to integrate the LMX1204 on a custom PCB board.
The purpose is to use the SYSREF in pulsed mode, issuing a request of pulses through SPI. I've followed the specification in the Datasheet and in the EVM Application note, and with SYSREF continuous i haven't any problems.
When i configure the SYSREF in pulsed mode, i expect a certain mode of operation, like issuing a SPI request (toogling the sysref request bit from 0 to 1, R72 (0x48) bit 2, i expect to see the number of pulses desired, but that not happens. When i set the bit to 0, the SYSREF output continuosly generate repeated pulses, when i set to 1, the SYSREF outputs go all to 0.
I figure out that, the expected result is obtained in the following way:
- Set SYSREF_MODE = SYNC -> @write R14(0x0E) 0x0000
- Set SYSREFREQ_SPI = LOW -> @write R72(0x48) 0x0000
- Set SYSREFREQ_SPI = HIGH -> @write R72(0x48) 0x0004
- Set SYSREF_MODE = SYSREF -> @write R14(0x0E) 0x0002
In this way, the output is the desired one like 8 pulses and after that the output is 0. Is supposed to work like that? I didn't expect this. I expect that the SYSREF_MODE remains set to SYSREF and only when i issue a LOW-HIGH transition on SYSREFREQ_SPI field the device outputs the desired number of pulses. I attach also the configuration file that i use in the TICS PRO.
Can someone helping me to issue that?
Thanks!
Best regards.
conf1+sysref_pulsed.tcs R90 0x5A0000
R86 0x560004
R79 0x4F0005
R75 0x4B0003
R72 0x480000
R67 0x4351CB
R65 0x4165F0
R34 0x2204C0
R33 0x210000
R29 0x1D05FF
R28 0x1C0A08
R25 0x190119
R24 0x180001
R23 0x17E040
R22 0x16046C
R21 0x15276C
R20 0x14276C
R19 0x13276C
R18 0x12276C
R17 0x110139
R16 0x108200
R15 0x0F0B80
R14 0x0E0000
R13 0x0D0001
R12 0x0C0000
R11 0x0B0000
R9 0x09C004
R8 0x080130
R7 0x070001
R6 0x06C924
R5 0x05493F
R4 0x043FFF
R3 0x033F87
R2 0x020083
R0 0x000000