| 为什么我的AT91SAM9263-EK ETM 信号有冲突 [TPK0 - TPK15]? |
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为什么我的AT91SAM9263-EK ETM 信号有冲突 [TPK0 - TPK15]? |
| Answer |
AT91SAM9263 的ETM 信号[TPK0 - TPK15] 与 EBI0 信号[EBI0_D16 - EBI0_D31]复用. 你需要去掉电阻R30来释放EBI0_NCS1_SDCS信号，并且把SDRAM的 IOs [EBI0_D16 - EBI0_D31]拉升至高阻状态. |
| Why my AT91SAM9263-EK ETM signals [TPK0 - TPK15] get corrupted? |
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Why my AT91SAM9263-EK ETM signals [TPK0 - TPK15] get corrupted? |
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AT91SAM9263 ETM signals [TPK0 - TPK15] are multiplexed with EBI0 signals [EBI0_D16 - EBI0_D31]. AT91SAM9263-EK EBI0 signals [EBI0_D16 - EBI0_D31] are connected to a SDRAM device (part MN7). The Chip Select connected to this SDRAM device (EBI0_NCS1_SDCS signal) is always asserted, which leads to keep this SDRAM device enabled. Having this SDRAM device enabled add capacitance on the data line [EBI0_D16 - EBI0_D31], which leads to data corruption. You need to remove the resistor R30 to release the EBI0_NCS1_SDCS signal and put the SDRAM IOs [EBI0_D16 - EBI0_D31] in High-Z. Having these signals in High-z removed the added capacitance, and then ETM signals [TPK0 - TPK15] will not be anymore corrupted. |
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为什么我的SDRAM的片选始终为低呢? |
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因为SDRAM内存被RAS/CAS/WE的组合信号选择访问，所以SDRAM 的片选被维持在低电平不会有任何问题。 |
| SDRAM Chip Select remains low |
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Why does my SDRAM Chip Select remain low? |
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The SDRAM Chip Select can remain low without any problems as the SDRAM memory is selected with a combination of RAS/CAS/WE signals. |
结论 : 可以直接把SDRAM的SDCS信号连接到GND, ARM 的SDCS 信号不用
在AT91SAM9261上面测试通过
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