The label printer requires some means of regulating the flow of data to and from the system to which they are attached. The suspension and resumption of data flow is necessary in a variety of circumstances. The attached PPT introduces a simple and effective flow control method running upon lwIP stack.
➢ IP protection is important for most customers, Kinetis, LPC54 series and i.MX RT have necessary security features that help us to win customers and markets. ➢ LPC55 series is a new generation of IoT MCU which is used for consumer and industrial market. LPC55 non-S parts are adopted by most customers due to its low-cost and easy-to-use features, but its secure features are different with S parts and is significantly simplified. ➢ LPC55 is designed for secured IoT application, so it’s supposed to hide the SWD/ISP ports after development work is finished. If the SWD/ISP ports are secured, they couldn’t be used any more. While for LPC54 & Kinetis MCU, mass erase command can be used to recover the MCU after the MCU is secured. ➢ However, Customers need the feature to secure the debugging/ISP ports, but they also need to recover them in some cases: - Reprogramming to update firmware - Investigate and analyze failed parts returned from end market - Rescue the MCU if it’s locked and stuck ➢ According to customers’ requirements, NXP support team raised the proposal to implement a solution which can be used to secure and recover the SWD/ISP ports with an IAP backdoor method.
By Operating PFR region, LPC55 could switch between secure and recovery mode.
lpc5506_debug_isp_test_20220714: demonstrate how to operate this region to lock Debug Port then how to recovery it. The user interaction could be raised by UART or button;
2.hmac_test_20220714: demonstrate one full security flow,
➢ This is a complete solution to secure & recovery debugging/ISP ports on LPC55, and it uses host machine challenge mechanism to implement security features: ▪ Challenge Host machine against unknown host probe; ▪ Generates dynamic seeds, so that the final encrypt information will be dynamically changed; ▪ The image hash value is device related, that avoids same encrypt info for different image/product;
➢ Customer also could clip the solution to simplify application complexity: ▪ Use UUID for device information only, no seed is needed; ▪ Host machine can use fixed keys instead of image hash values to do info encryption; ▪ Host machine can use UUID lookup table to find out verification key; Every device is programmed with dedicated verification key during production.
The attached demos could run at LPC55S06 EVK, and could easily migrate to other LPC55 series.
FAST BOOT FOR lx2160 IN adas
To speed up bringup of LX2 chip-based systems
•Pain Points to Address
The bringup time is much longer than 3s, which is very sensitive in ADAS systems or time-sensitive systems.
•Value Proposition / Key Features
The guide can help customers shorten uboot time from 5s to less than 1.5s, saving more than 70% bootup time.
Demo based on LX2160ARDB board.
Reference codes and patches.
Guide for Fast boot document.
Fast boot 广泛用于嵌入式设备，现以lx2160ardb板为例进行相关探索。 启动流程：
diff --git a/lx2160asi/flexspi_divisor_32.rcw b/lx2160asi/flexspi_divisor_32.rcw
index 422139c..0f8d5c9 100644
@@ -7,8 +7,10 @@
* Modify FlexSPICR1 register, to increase FlexSPI clock closer to 50MHz,
* with divisor value as 32.
* => 750 * 2 / 32 ==> 46.875MHz
+ *write 0x1e00900,0x00000013
+ * 0f -12 =125M
虽然目前NXP的很多MCU都带了丰富的UART资源，但是在某些特地的情况下或个别芯片，UART数量还是有一定的局限性。现在NXP很多的MCU也携带有FlexIO模块，那么我们就可以利用FlexIO来扩展更多的UART，SDK中有相应的代码，这些代码是支持全双工的，需要使用至少两个timer和两个shifter设计一个UART, 在实际使用中很多时候是使用半双工通信的，本文是基于SDK FlexIO的例程来设计基于一个timer和一个shifter的半双工UART，最大限度扩展UART数量，设计4个半双工的UART，本文设计验证平台为FRDEM-KE15Z和SDK_2.6.0_MKE15Z256xxx7。 希望能给需要的使用者提供种扩展尽可能多UART的方法。 Best Regards, Fred Fu