Xavier 上电启动概率失败问题

Hi,你好:

我们板卡的jetson Xavier上电时,偶发(但概率不低)上电失败。

现象

上电失败时,打印串口没有输出,但xavier reset信号正常拉高,代表系统根本没有进入boot。用示波器抓到,BOOT_SELECT1 、BOOT_SELECT2 上电配置管脚在上电失败时,电平异常: 本该拉低的信号,上电异常时,变为高电平。示波器测试波形如下图所示。

上电正常波形截图CH1: xavier_RST; CH2: BOOT_SELECT1; CH3: BOOT_SELECT2

上电异常波形截图CH1: xavier_RST; CH2: BOOT_SELECT1; CH3: BOOT_SELECT2

BOOT_SELECT1/2在我们电路板板上的设计如下。进一步测试,去掉外围电路,仍旧存在上述问题。

信号 Xavier内部 底板电路 补充说明
BOOT_SELECT1 ~100kΩ PD 中间串0ohm电阻,接到SN74AUP1G07DCKT(Single Buffer)的输入管脚

无其他上下拉电阻|去掉外部电阻,管脚悬空,仍旧出此问题|
|BOOT_SELECT2|~100kΩ PD|中间串0ohm电阻,接到TRS3122ERGE(232芯片)的发送管脚

无其他上下拉电阻|

疑问:

这个BOOT_SELECT1、2上电时电平异常的原因?能否提供解决问题的思路(外部用强下拉?)?

在《Jetson_AGX_Xavier_OEM_Product_Design_Guide.pdf》手册中,这两个管脚都有下拉电阻(虽然图中标注有下拉4.7Kohm,但实际用万用表测试,对地电阻仍未80Kohm左右)

Xavier 上电启动概率失败问题–210611赵字羽.docx (380.0 KB)

Hi, first you should do cross-check with devkit carrier board to make sure module has no problem. If no such issue on devkit with this module, then you should compare your board to P2822 to find out difference which might cause this issue. Also there is a checklist sheet in latest OEM DG in DLC, you should check your schematic based on that sheet one by one.

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