qhwxp
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I'm making a system of boundary scan and I use SN74ACT8990 to send JTAG signals which is controlled by STM32F103.
The connection of the microprocessor and ACT8990 is just right and I can read or write the registers of the ACT8990 correctly.
I use ACT8990 to extest the system. And I write the code which is the same as the example in the TI's issue "test bus controller"
(https://www.ti.com.cn/general/cn/do...tsp?baseLiteratureNumber=scaa044&fileType=pdf)
But I can't read the expected data from readbuffer as the issue told me.
Then I used probe to watch the signal of TDO of the ACT8990 and caught the wave.
I sent a 0x4321
The yellow wave is the TMS and the blue wave is the TDO.
And I find that the MSB of the 0x4321 is missing!
What is the problem?
Please some one answer me. Thanks!
The connection of the microprocessor and ACT8990 is just right and I can read or write the registers of the ACT8990 correctly.
I use ACT8990 to extest the system. And I write the code which is the same as the example in the TI's issue "test bus controller"
(https://www.ti.com.cn/general/cn/do...tsp?baseLiteratureNumber=scaa044&fileType=pdf)
But I can't read the expected data from readbuffer as the issue told me.
Then I used probe to watch the signal of TDO of the ACT8990 and caught the wave.
I sent a 0x4321
The yellow wave is the TMS and the blue wave is the TDO.
And I find that the MSB of the 0x4321 is missing!
What is the problem?
Please some one answer me. Thanks!
