Dear sirs,
Every time I write parameter to the register of PAGE, the ucd9240 will return me “connection refused”. I can’t change the rail, so I can only use the page 0, rail 1. Is the page command has something special? BTW, we don’t have the TI standard USB interface adapter.so we comunication ucd9240 with ARM (s3c2440 ,the pmbus comunication driver design by ourselfs)
Every time I write parameter to the register of PAGE, the ucd9240 will return me “connection refused”. I can’t change the rail, so I can only use the page 0, rail 1. Is the page command has something special?
BTW, we don’t have the TI standard USB interface adapter.so we comunication ucd9240 with ARM (s3c2440 ,the pmbus comunication driver design by ourselfs)
Two issues: (1) I enabled the function of PEC, but the PAGE command still does not work. From scope observation, I found that issuing other commands can produce the PEC field, but the PAGE command can NOT, please refer to the attached images for details. It seems that when issuing PAGE command, 9240 receives the DATA field and then immediately decides that the received data is invalid and responds with NACK. Thus the PEC field has no chance to be delivered. (2) Although the spec describes that after reset, all status bits of 9240 will be cleared. But experimentally we found that this is not true. In particular, the STATUS_BYTE and the STATUS WORD always read as 0x40.and we have powered to the VIN by12volt ,and has read the correct value in READ_VIN register(0x88h) We are very confused on these, and hope you can help us out.
Two issues:
(1) I enabled the function of PEC, but the PAGE command still does not work. From scope observation, I found that issuing other commands can produce the PEC field, but the PAGE command can NOT, please refer to the attached images for details.
It seems that when issuing PAGE command, 9240 receives the DATA field and then immediately decides that the received data is invalid and responds with NACK. Thus the PEC field has no chance to be delivered.
(2) Although the spec describes that after reset, all status bits of 9240 will be cleared. But experimentally we found that this is not true. In particular, the STATUS_BYTE and the STATUS WORD always read as 0x40.and we have powered to the VIN by12volt ,and has read the correct value in READ_VIN register(0x88h)
We are very confused on these, and hope you can help us out.
1) Has the UCD9240 device been configured prior to your issuing the PAGE command? An unconfigured part does not have any rails configured and will NACK the PAGE command. You will need to write the PHASE_INFO string, store it to flash and power cycle the device prior to being able to write paged PMBus parameters. If the part has been configured, how many output rails were setup using the PHASE_INFO command? If the device is configured as a single rail only then there is only one PAGE.
2) When all output are off the PMBus STATUS_WORD and STATUS_BYTE commands will return 0x0840 and 0x40 respectively. The two bits that are set are OFF and POWERGOOD#. These bits indicate that the device outputs are off and that all outputs are not above their POWER_GOOD_ON thresholds. This is normal. A STATUS_WORD of 0x0000 would indicate that only outputs are on and above their POWER_GOOD_ON thresholds.
If you have not configured the device, this document should help understand the process to configure the part.
http://focus.ti.com/lit/an/slua488/slua488.pdf
Karl Northrup
thanks for reply.
the issue has been fixed.
root cause: when the command of phase_info and store default all to carry out ,the ucd9240 will be reset.
solution: Add more decouple cap of 0.01uf near the power pin of UCD9240. It can guarantee PMBUS stability when transimitting large number of data.
But have new question
Does the ucd9240EVM support 12volt output ?
In my project ,power stage is controled by UCD7230. vin =15volt,double phase vout,FS=1MHZ,L=0.5uH,C=470uf*5+47uf*10,I want to get a adjustable Vout of 0 to 12volt. in the course of regulating, ofen burn down the low side MOSFET,ucd7230 is hot too, it will be better when configure single phase.would you share the reference circuit of ucd7230 and reference configure with me,would you share me the PTH08D110 SCH? thanks again!
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